CVE-2026-23209

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-23209", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.986Z", "datePublished": "2026-02-14T16:27:31.175Z", "dateUpdated": "2026-10-19T18:35:38.702Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:20:40.203Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmacvlan: fix error recovery in macvlan_common_newlink()\n\nvalis provided a nice repro to crash the kernel:\n\nip link add p1 type veth peer p2\nip link set address 00:00:00:00:00:20 dev p1\nip link set up dev p1\nip link set up dev p2\n\nip link add mv0 link p2 type macvlan mode source\nip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20\n\nping -c1 -I p1 1.2.3.4\n\nHe also gave a very detailed analysis:\n\n<quote valis>\n\nThe issue is triggered when a new macvlan link is created with\nMACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or\nMACVLAN_MACADDR_SET) parameter, lower device already has a macvlan\nport and register_netdevice() called from macvlan_common_newlink()\nfails (e.g. because of the invalid link name).\n\nIn this case macvlan_hash_add_source is called from\nmacvlan_change_sources() / macvlan_common_newlink():\n\nThis adds a reference to vlan to the port's vlan_source_hash using\nmacvlan_source_entry.\n\nvlan is a pointer to the priv data of the link that is being created.\n\nWhen register_netdevice() fails, the error is returned from\nmacvlan_newlink() to rtnl_newlink_create():\n\n if (ops->newlink)\n err = ops->newlink(dev, &params, extack);\n else\n err = register_netdevice(dev);\n if (err < 0) {\n free_netdev(dev);\n goto out;\n }\n\nand free_netdev() is called, causing a kvfree() on the struct\nnet_device that is still referenced in the source entry attached to\nthe lower device's macvlan port.\n\nNow all packets sent on the macvlan port with a matching source mac\naddress will trigger a use-after-free in macvlan_forward_source().\n\n</quote valis>\n\nWith all that, my fix is to make sure we call macvlan_flush_sources()\nregardless of @create value whenever \"goto destroy_macvlan_port;\"\npath is taken.\n\nMany thanks to valis for following up on this issue."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - Triggering the vulnerability requires CAP_NET_ADMIN to create macvlan interfaces, which is reachable via user namespaces (unshare -Urn) by an unprivileged local user. The setup is local even though the UAF is triggered by network packets.\nAC:L - The vulnerability is deterministically triggered by a straightforward sequence: create a macvlan source with a known-bad interface name to cause register_netdevice() failure, then send a packet with the matching source MAC. No race condition or special conditions needed.\nPR:L - Requires CAP_NET_ADMIN for RTM_NEWLINK netlink operations, but this capability is obtainable by any unprivileged user through user namespaces (unshare -Urn), as netlink_net_capable checks against the network namespace's user_ns, not init_user_ns.\nUI:N - No user interaction is needed. The attacker sets up the vulnerable macvlan configuration and triggers the UAF by sending packets on the lower device, all without any victim action.\nS:U - The vulnerability operates within the kernel's security context. While it allows kernel code execution, it does not cross a virtualization or sandbox boundary \u2014 it is standard kernel privilege escalation.\nC:H - The use-after-free in macvlan_forward_source() dereferences a freed macvlan_dev structure. An attacker can reclaim the freed memory via heap spraying, enabling arbitrary kernel memory reads through controlled object contents.\nI:H - The UAF accesses and writes to the freed macvlan_dev structure (e.g., macvlan_count_rx updates statistics). With heap spraying to reclaim the freed object, this provides arbitrary write primitives that can be leveraged for code execution.\nA:H - The use-after-free causes dereferencing of freed memory, which reliably causes kernel crashes (oops/panic) when the freed memory is reclaimed for other purposes. The reproducer in the commit message demonstrates a reliable crash."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/net/macvlan.c"], "versions": [{"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "da5c6b8ae47e414be47e5e04def15b25d5c962dc", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "c43d0e787cbba569ec9d11579ed370b50fab6c9c", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "11ba9f0dc865136174cb98834280fb21bbc950c7", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "986967a162142710076782d5b93daab93a892980", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "f8db6475a83649689c087a8f52486fcc53e627e9", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/net/macvlan.c"], "versions": [{"version": "4.9", "status": "affected"}, {"version": "0", "lessThan": "4.9", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.250", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.200", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.163", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.124", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.70", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.10", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.10.250"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.15.200"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.1.163"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.6.124"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.12.70"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.18.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.19"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/da5c6b8ae47e414be47e5e04def15b25d5c962dc"}, {"url": "https://git.kernel.org/stable/c/5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a"}, {"url": "https://git.kernel.org/stable/c/c43d0e787cbba569ec9d11579ed370b50fab6c9c"}, {"url": "https://git.kernel.org/stable/c/11ba9f0dc865136174cb98834280fb21bbc950c7"}, {"url": "https://git.kernel.org/stable/c/986967a162142710076782d5b93daab93a892980"}, {"url": "https://git.kernel.org/stable/c/cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66"}, {"url": "https://git.kernel.org/stable/c/f8db6475a83649689c087a8f52486fcc53e627e9"}], "title": "macvlan: fix error recovery in macvlan_common_newlink()", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-23209", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-06-16T20:31:00.910619Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free"}]}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-19T18:35:38.702Z"}}]}}

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-23209", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.986Z", "datePublished": "2026-02-14T16:27:31.175Z", "dateUpdated": "2026-10-19T18:35:38.702Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:20:40.203Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmacvlan: fix error recovery in macvlan_common_newlink()\n\nvalis provided a nice repro to crash the kernel:\n\nip link add p1 type veth peer p2\nip link set address 00:00:00:00:00:20 dev p1\nip link set up dev p1\nip link set up dev p2\n\nip link add mv0 link p2 type macvlan mode source\nip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20\n\nping -c1 -I p1 1.2.3.4\n\nHe also gave a very detailed analysis:\n\n<quote valis>\n\nThe issue is triggered when a new macvlan link is created with\nMACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or\nMACVLAN_MACADDR_SET) parameter, lower device already has a macvlan\nport and register_netdevice() called from macvlan_common_newlink()\nfails (e.g. because of the invalid link name).\n\nIn this case macvlan_hash_add_source is called from\nmacvlan_change_sources() / macvlan_common_newlink():\n\nThis adds a reference to vlan to the port's vlan_source_hash using\nmacvlan_source_entry.\n\nvlan is a pointer to the priv data of the link that is being created.\n\nWhen register_netdevice() fails, the error is returned from\nmacvlan_newlink() to rtnl_newlink_create():\n\n if (ops->newlink)\n err = ops->newlink(dev, &params, extack);\n else\n err = register_netdevice(dev);\n if (err < 0) {\n free_netdev(dev);\n goto out;\n }\n\nand free_netdev() is called, causing a kvfree() on the struct\nnet_device that is still referenced in the source entry attached to\nthe lower device's macvlan port.\n\nNow all packets sent on the macvlan port with a matching source mac\naddress will trigger a use-after-free in macvlan_forward_source().\n\n</quote valis>\n\nWith all that, my fix is to make sure we call macvlan_flush_sources()\nregardless of @create value whenever \"goto destroy_macvlan_port;\"\npath is taken.\n\nMany thanks to valis for following up on this issue."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - Triggering the vulnerability requires CAP_NET_ADMIN to create macvlan interfaces, which is reachable via user namespaces (unshare -Urn) by an unprivileged local user. The setup is local even though the UAF is triggered by network packets.\nAC:L - The vulnerability is deterministically triggered by a straightforward sequence: create a macvlan source with a known-bad interface name to cause register_netdevice() failure, then send a packet with the matching source MAC. No race condition or special conditions needed.\nPR:L - Requires CAP_NET_ADMIN for RTM_NEWLINK netlink operations, but this capability is obtainable by any unprivileged user through user namespaces (unshare -Urn), as netlink_net_capable checks against the network namespace's user_ns, not init_user_ns.\nUI:N - No user interaction is needed. The attacker sets up the vulnerable macvlan configuration and triggers the UAF by sending packets on the lower device, all without any victim action.\nS:U - The vulnerability operates within the kernel's security context. While it allows kernel code execution, it does not cross a virtualization or sandbox boundary \u2014 it is standard kernel privilege escalation.\nC:H - The use-after-free in macvlan_forward_source() dereferences a freed macvlan_dev structure. An attacker can reclaim the freed memory via heap spraying, enabling arbitrary kernel memory reads through controlled object contents.\nI:H - The UAF accesses and writes to the freed macvlan_dev structure (e.g., macvlan_count_rx updates statistics). With heap spraying to reclaim the freed object, this provides arbitrary write primitives that can be leveraged for code execution.\nA:H - The use-after-free causes dereferencing of freed memory, which reliably causes kernel crashes (oops/panic) when the freed memory is reclaimed for other purposes. The reproducer in the commit message demonstrates a reliable crash."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/net/macvlan.c"], "versions": [{"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "da5c6b8ae47e414be47e5e04def15b25d5c962dc", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "c43d0e787cbba569ec9d11579ed370b50fab6c9c", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "11ba9f0dc865136174cb98834280fb21bbc950c7", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "986967a162142710076782d5b93daab93a892980", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66", "status": "affected", "versionType": "git"}, {"version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "lessThan": "f8db6475a83649689c087a8f52486fcc53e627e9", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/net/macvlan.c"], "versions": [{"version": "4.9", "status": "affected"}, {"version": "0", "lessThan": "4.9", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.250", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.200", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.163", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.124", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.70", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.10", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.10.250"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "5.15.200"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.1.163"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.6.124"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.12.70"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.18.10"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9", "versionEndExcluding": "6.19"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/da5c6b8ae47e414be47e5e04def15b25d5c962dc"}, {"url": "https://git.kernel.org/stable/c/5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a"}, {"url": "https://git.kernel.org/stable/c/c43d0e787cbba569ec9d11579ed370b50fab6c9c"}, {"url": "https://git.kernel.org/stable/c/11ba9f0dc865136174cb98834280fb21bbc950c7"}, {"url": "https://git.kernel.org/stable/c/986967a162142710076782d5b93daab93a892980"}, {"url": "https://git.kernel.org/stable/c/cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66"}, {"url": "https://git.kernel.org/stable/c/f8db6475a83649689c087a8f52486fcc53e627e9"}], "title": "macvlan: fix error recovery in macvlan_common_newlink()", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-23209", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-06-16T20:31:00.910619Z"}}}], "problemTypes": [{"descriptions": [{"lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free"}]}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-16T20:31:06.981Z"}, "title": "CISA ADP Vulnrichment"}]}}

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"versionType": "git"}, {"lessThan": "cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66", "status": "affected", "version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "versionType": "git"}, {"lessThan": "f8db6475a83649689c087a8f52486fcc53e627e9", "status": "affected", "version": "aa5fd0fb77486b8a6764ead8627baa14790e4280", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/net/macvlan.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.9"}, {"lessThan": "4.9", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.250", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.200", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.163", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.124", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.70", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.10", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "6.19", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "93494E82-FEAE-4F5D-9065-D14C28E8B045", "versionEndExcluding": "5.10.250", "versionStartIncluding": "4.9.1", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": "D16F6370-B70F-471C-8363-3A17B0BB1DA9", "versionEndExcluding": "5.15.200", "versionStartIncluding": "5.11", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "matchCriteriaId": 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"B0288B1E-67AB-40F4-98C7-8C686510F664", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:4.9:rc7:*:*:*:*:*:*", "matchCriteriaId": "73A5C6E1-051D-4FDC-8034-BE2896C639F3", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:4.9:rc8:*:*:*:*:*:*", "matchCriteriaId": "F96570B2-47BE-4DEF-AAD8-909913366EA0", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*", "matchCriteriaId": "17B67AA7-40D6-4AFA-8459-F200F3D7CFD1", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:*", "matchCriteriaId": "C47E4CC9-C826-4FA9-B014-7FE3D9B318B2", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:*", "matchCriteriaId": "F71D92C0-C023-48BD-B3B6-70B638EEE298", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:*", "matchCriteriaId": "13580667-0A98-40CC-B29F-D12790B91BDB", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:*", "matchCriteriaId": "CAD1FED7-CF48-47BF-AC7D-7B6FA3C065FC", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:*", "matchCriteriaId": "3EF854A1-ABB1-4E93-BE9A-44569EC76C0D", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:*", "matchCriteriaId": "F5DC0CA6-F0AF-4DDF-A882-3DADB9A886A7", "vulnerable": true}, {"criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:*", "matchCriteriaId": "EB5B7DFC-C36B-45D8-922C-877569FDDF43", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmacvlan: fix error recovery in macvlan_common_newlink()\n\nvalis provided a nice repro to crash the kernel:\n\nip link add p1 type veth peer p2\nip link set address 00:00:00:00:00:20 dev p1\nip link set up dev p1\nip link set up dev p2\n\nip link add mv0 link p2 type macvlan mode source\nip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20\n\nping -c1 -I p1 1.2.3.4\n\nHe also gave a very detailed analysis:\n\n<quote valis>\n\nThe issue is triggered when a new macvlan link is created with\nMACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or\nMACVLAN_MACADDR_SET) parameter, lower device already has a macvlan\nport and register_netdevice() called from macvlan_common_newlink()\nfails (e.g. because of the invalid link name).\n\nIn this case macvlan_hash_add_source is called from\nmacvlan_change_sources() / macvlan_common_newlink():\n\nThis adds a reference to vlan to the port's vlan_source_hash using\nmacvlan_source_entry.\n\nvlan is a pointer to the priv data of the link that is being created.\n\nWhen register_netdevice() fails, the error is returned from\nmacvlan_newlink() to rtnl_newlink_create():\n\n if (ops->newlink)\n err = ops->newlink(dev, &params, extack);\n else\n err = register_netdevice(dev);\n if (err < 0) {\n free_netdev(dev);\n goto out;\n }\n\nand free_netdev() is called, causing a kvfree() on the struct\nnet_device that is still referenced in the source entry attached to\nthe lower device's macvlan port.\n\nNow all packets sent on the macvlan port with a matching source mac\naddress will trigger a use-after-free in macvlan_forward_source().\n\n</quote valis>\n\nWith all that, my fix is to make sure we call macvlan_flush_sources()\nregardless of @create value whenever \"goto destroy_macvlan_port;\"\npath is taken.\n\nMany thanks to valis for following up on this issue."}, {"lang": "es", "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nmacvlan: arreglar la recuperaci\u00f3n de errores en macvlan_common_newlink()\n\nvalis proporcion\u00f3 una buena reproducci\u00f3n para colapsar el kernel:\n\nip link add p1 type veth peer p2\nip link set address 00:00:00:00:00:20 dev p1\nip link set up dev p1\nip link set up dev p2\n\nip link add mv0 link p2 type macvlan mode source\nip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20\n\nping -c1 -I p1 1.2.3.4\n\nTambi\u00e9n proporcion\u00f3 un an\u00e1lisis muy detallado:\n\n'El problema se activa cuando se crea un nuevo enlace macvlan con el modo MACVLAN_MODE_SOURCE y el par\u00e1metro MACVLAN_MACADDR_ADD (o MACVLAN_MACADDR_SET), el dispositivo inferior ya tiene un puerto macvlan y register_netdevice() llamado desde macvlan_common_newlink() falla (por ejemplo, debido al nombre de enlace no v\u00e1lido).\n\nEn este caso, macvlan_hash_add_source es llamado desde macvlan_change_sources() / macvlan_common_newlink():\n\nEsto a\u00f1ade una referencia a vlan al vlan_source_hash del puerto usando macvlan_source_entry.\n\nvlan es un puntero a los datos privados del enlace que se est\u00e1 creando.\n\nCuando register_netdevice() falla, el error es devuelto desde macvlan_newlink() a rtnl_newlink_create():\n\n if (ops-&gt;newlink)\n err = ops-&gt;newlink(dev, &amp;params, extack);\n else\n err = register_netdevice(dev);\n if (err &lt; 0) {\n free_netdev(dev);\n goto out;\n }\n\ny se llama a free_netdev(), causando un kvfree() en la estructura net_device que todav\u00eda est\u00e1 referenciada en la entrada de origen adjunta al puerto macvlan del dispositivo inferior.\n\nAhora, todos los paquetes enviados en el puerto macvlan con una direcci\u00f3n MAC de origen coincidente activar\u00e1n un uso despu\u00e9s de liberaci\u00f3n en macvlan_forward_source().'\n\nCon todo eso, mi soluci\u00f3n es asegurarme de que llamamos a macvlan_flush_sources() independientemente del valor de @create cada vez que se toma la ruta \"goto destroy_macvlan_port;\".\n\nMuchas gracias a valis por hacer seguimiento de este problema."}], "id": "CVE-2026-23209", "lastModified": "2026-10-19T19:17:41.920", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-23209", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-06-16T20:31:00.910619Z", "version": "2.0.3"}}]}, "published": "2026-02-14T17:15:58.803", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/11ba9f0dc865136174cb98834280fb21bbc950c7"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/986967a162142710076782d5b93daab93a892980"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/c43d0e787cbba569ec9d11579ed370b50fab6c9c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/da5c6b8ae47e414be47e5e04def15b25d5c962dc"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"], "url": "https://git.kernel.org/stable/c/f8db6475a83649689c087a8f52486fcc53e627e9"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "nvd@nist.gov", "type": "Primary"}, {"description": [{"lang": "en", "value": "CWE-416"}], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "type": "Secondary"}]}

{"bugzilla": {"description": "kernel: macvlan: fix error recovery in macvlan_common_newlink()", "id": "2439900", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2439900"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "details": ["In the Linux kernel, the following vulnerability has been resolved:\nmacvlan: fix error recovery in macvlan_common_newlink()\nvalis provided a nice repro to crash the kernel:\nip link add p1 type veth peer p2\nip link set address 00:00:00:00:00:20 dev p1\nip link set up dev p1\nip link set up dev p2\nip link add mv0 link p2 type macvlan mode source\nip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20\nping -c1 -I p1 1.2.3.4\nHe also gave a very detailed analysis:\n<quote valis>\nThe issue is triggered when a new macvlan link is created with\nMACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or\nMACVLAN_MACADDR_SET) parameter, lower device already has a macvlan\nport and register_netdevice() called from macvlan_common_newlink()\nfails (e.g. because of the invalid link name).\nIn this case macvlan_hash_add_source is called from\nmacvlan_change_sources() / macvlan_common_newlink():\nThis adds a reference to vlan to the port's vlan_source_hash using\nmacvlan_source_entry.\nvlan is a pointer to the priv data of the link that is being created.\nWhen register_netdevice() fails, the error is returned from\nmacvlan_newlink() to rtnl_newlink_create():\nif (ops->newlink)\nerr = ops->newlink(dev, &params, extack);\nelse\nerr = register_netdevice(dev);\nif (err < 0) {\nfree_netdev(dev);\ngoto out;\n}\nand free_netdev() is called, causing a kvfree() on the struct\nnet_device that is still referenced in the source entry attached to\nthe lower device's macvlan port.\nNow all packets sent on the macvlan port with a matching source mac\naddress will trigger a use-after-free in macvlan_forward_source().\n</quote valis>\nWith all that, my fix is to make sure we call macvlan_flush_sources()\nregardless of @create value whenever \"goto destroy_macvlan_port;\"\npath is taken.\nMany thanks to valis for following up on this issue."], "name": "CVE-2026-23209", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Under investigation", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-02-14T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-23209\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-23209\nhttps://lore.kernel.org/linux-cve-announce/2026021439-CVE-2026-23209-9ad6@gregkh/T"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa5fd0fb77486b8a6764ead8627baa14790e4280,da5c6b8ae47e414be47e5e04def15b25d5c962dc)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa5fd0fb77486b8a6764ead8627baa14790e4280,5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa5fd0fb77486b8a6764ead8627baa14790e4280,c43d0e787cbba569ec9d11579ed370b50fab6c9c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa5fd0fb77486b8a6764ead8627baa14790e4280,11ba9f0dc865136174cb98834280fb21bbc950c7)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa5fd0fb77486b8a6764ead8627baa14790e4280,986967a162142710076782d5b93daab93a892980)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa5fd0fb77486b8a6764ead8627baa14790e4280,cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa5fd0fb77486b8a6764ead8627baa14790e4280,f8db6475a83649689c087a8f52486fcc53e627e9)"}}], "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.9"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,4.9)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.10.250,5.11.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[5.15.200,5.16.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.163,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.124,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.70,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.10,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.19,*]"}}], "product": "linux_kernel", "vendor": "linux"}], "analysis": {"en": {"generated_at": "2026-04-16T00:42:26.749003+00:00", "value": {"mitigation_remediation": ["Upgrade the kernel to a version that includes the fix in commit\u202f11ba9f0dc865 (or any newer kernel that contains the error\u2011recovery patch for macvlan_common_newlink).", "If a kernel upgrade is not immediately possible, disable the creation of macvlan interfaces in SOURCE mode or remove the MACADDR_ADD/SET options for any existing interfaces.", "As a temporary measure, remove or restrict the capabilities that allow a process to create network interfaces (e.g., revoke NET_ADMIN or CAP_NET_ADMIN from untrusted users) until the kernel patch can be applied."], "summary": {"action": "Apply Patch", "impact": "Denial of Service with possible kernel crash"}, "threat_synthesis": {"affected_systems": "All Linux kernels are affected, from version\u202f4.9 through at least\u202f6.19\u2011rc8, as indicated by the CPE list. The vulnerability is present in the mainline kernel, so any distribution that has not yet released a patched kernel version will be vulnerable. The flaw applies to any system that can create macvlan interfaces in SOURCE mode, which typically requires root or equivalent privileges.", "description_and_impact": "The Linux kernel contains a use\u2011after\u2011free flaw in the macvlan subsystem. When a macvlan interface is created in SOURCE mode with the MACADDR_ADD or MACADDR_SET option, and the underlying register_netdevice() call fails (for example, due to an invalid link name), the kernel incorrectly leaves a reference to the freed net_device in a hash table. Subsequent packets routed through the macvlan port with a matching source MAC address trigger a use\u2011after\u2011free in macvlan_forward_source(), which can crash the kernel. The CVSS score of 7.8 classifies the flaw as high severity.", "risk_and_exploitability": "The likelihood of exploitation is low, with an EPSS score of less than\u202f1%, and the vulnerability is not listed in CISA\u2019s Known Exploited Vulnerabilities catalog. An attacker would need the ability to create macvlan interfaces and send traffic that triggers the use\u2011after\u2011free, implying a privileged local attack. No publicly available exploit code has been reported, but a kernel panic can be reproduced with a simple script, indicating that exploitation could be achieved with moderate skill and the appropriate permissions."}}}}, "created": "2026-02-16T09:43:22.336599+00:00", "updated": "2026-04-16T00:45:15.973997+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}