CVE-2026-89555

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89555", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.724Z", "datePublished": "2026-09-11T19:44:28.331Z", "dateUpdated": "2026-10-19T08:48:48.093Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:48:48.093Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmpls: reload header after pskb_may_pull()\n\nmpls_select_multipath() calls mpls_multipath_hash() to choose a nexthop\nwhen an MPLS route has multiple nexthops. While walking the MPLS label\nstack, the hash routine caches hdr for the current label. After finding\nthe bottom-of-stack label, it calls pskb_may_pull() before reading the\ninner IP header.\n\nIf an skb is constructed with the inner IP header in nonlinear data and\ninsufficient tailroom in the linear head, pskb_may_pull() calls\npskb_expand_head() to replace the skb head and free the old one. This\nleaves hdr pointing to freed memory. The IPv6 path can invalidate hdr\nagain when it performs a second pull for the larger header.\n\nThe issue was found through static analysis. A reproducer sending a legal\nGeneve packet through a bareudp/MPLS multipath setup triggered the same\nKASAN report in 2 of 2 unpatched runs:\n\n BUG: KASAN: slab-use-after-free in mpls_select_multipath\n Read of size 1 at addr ffff88800ecc6e20 by task ksoftirqd/1/23\n\n Call Trace:\n mpls_select_multipath\n mpls_forward\n __netif_receive_skb_list_core\n netif_receive_skb_list_internal\n napi_complete_done\n gro_cell_poll\n __napi_poll\n net_rx_action\n\n Freed by task 23:\n kfree\n pskb_expand_head\n __pskb_pull_tail\n mpls_select_multipath\n\nReload hdr from the current skb head after each successful pull before\nderiving the inner IPv4 or IPv6 header pointer."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL"}, "scenarios": [{"lang": "en", "value": "AV:N - mpls_forward() is the ETH_P_MPLS_UC packet_type receive handler; remote MPLS-in-IP (IPPROTO_MPLS), MPLS-over-UDP/bareudp, Geneve, and IPIP/SIT/ip6 tunnels deliver inner MPLS into this path without local access, matching the Geneve/bareudp KASAN reproducer.\nAC:L - An attacker sending MPLS or tunneled overlay frames fully controls the label stack, BOS bit, and skb layout; GRO/tunnel decap yields nonlinear skbs so pskb_may_pull() reallocates skb->head, and the unpatched Geneve reproducer hit the UAF in 2 of 2 runs with no victim-timed race.\nPR:N - Exploitation needs only unauthenticated packets that hit an already configured MPLS-enabled interface and multipath label route; mpls_forward() performs no credential check, and enabling MPLS input or tunnels is victim deployment rather than an attacker privilege.\nUI:N - The use-after-free runs in softirq receive processing (gro_cell_poll / netif_receive_skb_list) as soon as the crafted frame is accepted; no local user or administrator action is required beyond normal forwarding.\nS:U - The stale MPLS header pointer is a heap use-after-free inside the same host kernel MPLS forwarding path; impact stays within that kernel security authority and does not cross a VM, IOMMU, or other boundary.\nC:H - After pskb_expand_head() frees the old skb head, mpls_multipath_hash() reads the inner IPv4/IPv6 header through the stale hdr pointer, a slab use-after-free that can disclose freed kmalloc contents and is scored as high-impact kernel information disclosure.\nI:H - The immediate stale access is a header read used for ECMP hashing, but it remains a kernel slab use-after-free of skb->head; attacker-controlled reclaim of the freed kmalloc object is a well-established path to heap corruption and control-flow hijacking.\nA:H - KASAN confirmed a slab-use-after-free in mpls_select_multipath() on the forwarding path; dereferencing the freed skb head can oops or panic the kernel, and UAFs remain a high-impact denial of service even without full exploitation."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/mpls/af_mpls.c"], "versions": [{"version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "aa4fe0b450a461aa1162fe8375f5d28f4c957df8", "status": "affected", "versionType": "git"}, {"version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "b1c0783b2facc398437ad8f8b86c636d7a78f8db", "status": "affected", "versionType": "git"}, {"version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "bfaaff99238326166694354a63a76c02563f98b1", "status": "affected", "versionType": "git"}, {"version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "d9640239827d6d0cb84263b590f7a4f1596c17eb", "status": "affected", "versionType": "git"}, {"version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "fed638a248116b8a249bd4202d28e5934bdc65ad", "status": "affected", "versionType": "git"}, {"version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "d82b90a38c2ca8a0694428eab0e9551c23f2447d", "status": "affected", "versionType": "git"}, {"version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "49d38c1b4390412f8950d33dfaee0ccbd17beb81", "status": "affected", "versionType": "git"}, {"version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "29e63b8d9fc150cc191b1c6eb7e16e1247e1b650", "status": "affected", "versionType": "git"}, {"version": "ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb", "status": "affected", "versionType": "git"}, {"version": "4.9.8", "lessThan": "4.10", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/mpls/af_mpls.c"], "versions": [{"version": "4.10", "status": "affected"}, {"version": "0", "lessThan": "4.10", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "4.10", "versionEndExcluding": "5.10.270"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "5.15.221"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "6.1.188"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "6.6.157"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "7.3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9.8"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/aa4fe0b450a461aa1162fe8375f5d28f4c957df8"}, {"url": "https://git.kernel.org/stable/c/b1c0783b2facc398437ad8f8b86c636d7a78f8db"}, {"url": "https://git.kernel.org/stable/c/bfaaff99238326166694354a63a76c02563f98b1"}, {"url": "https://git.kernel.org/stable/c/d9640239827d6d0cb84263b590f7a4f1596c17eb"}, {"url": "https://git.kernel.org/stable/c/fed638a248116b8a249bd4202d28e5934bdc65ad"}, {"url": "https://git.kernel.org/stable/c/d82b90a38c2ca8a0694428eab0e9551c23f2447d"}, {"url": "https://git.kernel.org/stable/c/49d38c1b4390412f8950d33dfaee0ccbd17beb81"}, {"url": "https://git.kernel.org/stable/c/29e63b8d9fc150cc191b1c6eb7e16e1247e1b650"}], "title": "mpls: reload header after pskb_may_pull()", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89555", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T19:24:02.263001Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:43.764Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89555", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T19:24:02.263001Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:24:04.475Z"}}], "cna": {"title": "mpls: reload header after pskb_may_pull()", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 9.8, "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:N - mpls_forward() is the ETH_P_MPLS_UC packet_type receive handler; remote MPLS-in-IP (IPPROTO_MPLS), MPLS-over-UDP/bareudp, Geneve, and IPIP/SIT/ip6 tunnels deliver inner MPLS into this path without local access, matching the Geneve/bareudp KASAN reproducer.\nAC:L - An attacker sending MPLS or tunneled overlay frames fully controls the label stack, BOS bit, and skb layout; GRO/tunnel decap yields nonlinear skbs so pskb_may_pull() reallocates skb->head, and the unpatched Geneve reproducer hit the UAF in 2 of 2 runs with no victim-timed race.\nPR:N - Exploitation needs only unauthenticated packets that hit an already configured MPLS-enabled interface and multipath label route; mpls_forward() performs no credential check, and enabling MPLS input or tunnels is victim deployment rather than an attacker privilege.\nUI:N - The use-after-free runs in softirq receive processing (gro_cell_poll / netif_receive_skb_list) as soon as the crafted frame is accepted; no local user or administrator action is required beyond normal forwarding.\nS:U - The stale MPLS header pointer is a heap use-after-free inside the same host kernel MPLS forwarding path; impact stays within that kernel security authority and does not cross a VM, IOMMU, or other boundary.\nC:H - After pskb_expand_head() frees the old skb head, mpls_multipath_hash() reads the inner IPv4/IPv6 header through the stale hdr pointer, a slab use-after-free that can disclose freed kmalloc contents and is scored as high-impact kernel information disclosure.\nI:H - The immediate stale access is a header read used for ECMP hashing, but it remains a kernel slab use-after-free of skb->head; attacker-controlled reclaim of the freed kmalloc object is a well-established path to heap corruption and control-flow hijacking.\nA:H - KASAN confirmed a slab-use-after-free in mpls_select_multipath() on the forwarding path; dereferencing the freed skb head can oops or panic the kernel, and UAFs remain a high-impact denial of service even without full exploitation."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "aa4fe0b450a461aa1162fe8375f5d28f4c957df8", "versionType": "git"}, {"status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "b1c0783b2facc398437ad8f8b86c636d7a78f8db", "versionType": "git"}, {"status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "bfaaff99238326166694354a63a76c02563f98b1", "versionType": "git"}, {"status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "d9640239827d6d0cb84263b590f7a4f1596c17eb", "versionType": "git"}, {"status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "fed638a248116b8a249bd4202d28e5934bdc65ad", "versionType": "git"}, {"status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "d82b90a38c2ca8a0694428eab0e9551c23f2447d", "versionType": "git"}, {"status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "49d38c1b4390412f8950d33dfaee0ccbd17beb81", "versionType": "git"}, {"status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "lessThan": "29e63b8d9fc150cc191b1c6eb7e16e1247e1b650", "versionType": "git"}, {"status": "affected", "version": "ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb", "versionType": "git"}, {"status": "affected", "version": "4.9.8", "lessThan": "4.10", "versionType": "semver"}], "programFiles": ["net/mpls/af_mpls.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "4.10"}, {"status": "unaffected", "version": "0", "lessThan": "4.10", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.270", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.221", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.188", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.157", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.109", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.50", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.2.4", "versionType": "semver", "lessThanOrEqual": "7.2.*"}, {"status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/mpls/af_mpls.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/aa4fe0b450a461aa1162fe8375f5d28f4c957df8"}, {"url": "https://git.kernel.org/stable/c/b1c0783b2facc398437ad8f8b86c636d7a78f8db"}, {"url": "https://git.kernel.org/stable/c/bfaaff99238326166694354a63a76c02563f98b1"}, {"url": "https://git.kernel.org/stable/c/d9640239827d6d0cb84263b590f7a4f1596c17eb"}, {"url": "https://git.kernel.org/stable/c/fed638a248116b8a249bd4202d28e5934bdc65ad"}, {"url": "https://git.kernel.org/stable/c/d82b90a38c2ca8a0694428eab0e9551c23f2447d"}, {"url": "https://git.kernel.org/stable/c/49d38c1b4390412f8950d33dfaee0ccbd17beb81"}, {"url": "https://git.kernel.org/stable/c/29e63b8d9fc150cc191b1c6eb7e16e1247e1b650"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmpls: reload header after pskb_may_pull()\n\nmpls_select_multipath() calls mpls_multipath_hash() to choose a nexthop\nwhen an MPLS route has multiple nexthops. While walking the MPLS label\nstack, the hash routine caches hdr for the current label. After finding\nthe bottom-of-stack label, it calls pskb_may_pull() before reading the\ninner IP header.\n\nIf an skb is constructed with the inner IP header in nonlinear data and\ninsufficient tailroom in the linear head, pskb_may_pull() calls\npskb_expand_head() to replace the skb head and free the old one. This\nleaves hdr pointing to freed memory. The IPv6 path can invalidate hdr\nagain when it performs a second pull for the larger header.\n\nThe issue was found through static analysis. A reproducer sending a legal\nGeneve packet through a bareudp/MPLS multipath setup triggered the same\nKASAN report in 2 of 2 unpatched runs:\n\n BUG: KASAN: slab-use-after-free in mpls_select_multipath\n Read of size 1 at addr ffff88800ecc6e20 by task ksoftirqd/1/23\n\n Call Trace:\n mpls_select_multipath\n mpls_forward\n __netif_receive_skb_list_core\n netif_receive_skb_list_internal\n napi_complete_done\n gro_cell_poll\n __napi_poll\n net_rx_action\n\n Freed by task 23:\n kfree\n pskb_expand_head\n __pskb_pull_tail\n mpls_select_multipath\n\nReload hdr from the current skb head after each successful pull before\nderiving the inner IPv4 or IPv6 header pointer."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.270", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.221", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.188", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.157", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.109", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.50", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.2.4", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.3", "versionStartIncluding": "4.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionStartIncluding": "4.9.8"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:48:48.093Z"}}}, "cveMetadata": {"cveId": "CVE-2026-89555", "state": "PUBLISHED", "dateUpdated": "2026-10-19T08:48:48.093Z", "dateReserved": "2026-09-11T19:38:34.724Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-09-11T19:44:28.331Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/mpls/af_mpls.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "aa4fe0b450a461aa1162fe8375f5d28f4c957df8", "status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "versionType": "git"}, {"lessThan": "b1c0783b2facc398437ad8f8b86c636d7a78f8db", "status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "versionType": "git"}, {"lessThan": "bfaaff99238326166694354a63a76c02563f98b1", "status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "versionType": "git"}, {"lessThan": "d9640239827d6d0cb84263b590f7a4f1596c17eb", "status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "versionType": "git"}, {"lessThan": "fed638a248116b8a249bd4202d28e5934bdc65ad", "status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "versionType": "git"}, {"lessThan": "d82b90a38c2ca8a0694428eab0e9551c23f2447d", "status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "versionType": "git"}, {"lessThan": "49d38c1b4390412f8950d33dfaee0ccbd17beb81", "status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "versionType": "git"}, {"lessThan": "29e63b8d9fc150cc191b1c6eb7e16e1247e1b650", "status": "affected", "version": "9f427a0e474a67b454420c131709600d44850486", "versionType": "git"}, {"status": "affected", "version": "ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb", "versionType": "git"}, {"lessThan": "4.10", "status": "affected", "version": "4.9.8", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/mpls/af_mpls.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.10"}, {"lessThan": "4.10", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.270", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.221", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.188", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.157", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.109", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmpls: reload header after pskb_may_pull()\n\nmpls_select_multipath() calls mpls_multipath_hash() to choose a nexthop\nwhen an MPLS route has multiple nexthops. While walking the MPLS label\nstack, the hash routine caches hdr for the current label. After finding\nthe bottom-of-stack label, it calls pskb_may_pull() before reading the\ninner IP header.\n\nIf an skb is constructed with the inner IP header in nonlinear data and\ninsufficient tailroom in the linear head, pskb_may_pull() calls\npskb_expand_head() to replace the skb head and free the old one. This\nleaves hdr pointing to freed memory. The IPv6 path can invalidate hdr\nagain when it performs a second pull for the larger header.\n\nThe issue was found through static analysis. A reproducer sending a legal\nGeneve packet through a bareudp/MPLS multipath setup triggered the same\nKASAN report in 2 of 2 unpatched runs:\n\n BUG: KASAN: slab-use-after-free in mpls_select_multipath\n Read of size 1 at addr ffff88800ecc6e20 by task ksoftirqd/1/23\n\n Call Trace:\n mpls_select_multipath\n mpls_forward\n __netif_receive_skb_list_core\n netif_receive_skb_list_internal\n napi_complete_done\n gro_cell_poll\n __napi_poll\n net_rx_action\n\n Freed by task 23:\n kfree\n pskb_expand_head\n __pskb_pull_tail\n mpls_select_multipath\n\nReload hdr from the current skb head after each successful pull before\nderiving the inner IPv4 or IPv6 header pointer."}], "id": "CVE-2026-89555", "lastModified": "2026-10-19T09:17:50.940", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 9.8, "baseSeverity": "CRITICAL", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-89555", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T19:24:02.263001Z", "version": "2.0.3"}}]}, "published": "2026-09-11T20:19:39.147", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/29e63b8d9fc150cc191b1c6eb7e16e1247e1b650"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/49d38c1b4390412f8950d33dfaee0ccbd17beb81"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/aa4fe0b450a461aa1162fe8375f5d28f4c957df8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b1c0783b2facc398437ad8f8b86c636d7a78f8db"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bfaaff99238326166694354a63a76c02563f98b1"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d82b90a38c2ca8a0694428eab0e9551c23f2447d"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d9640239827d6d0cb84263b590f7a4f1596c17eb"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fed638a248116b8a249bd4202d28e5934bdc65ad"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: MPLS use-after-free vulnerability causes denial of service.", "id": "2532032", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532032"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.9", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["A flaw was found in the Linux kernel's Multiprotocol Label Switching (MPLS) subsystem. When processing specially crafted Geneve packets through an MPLS multipath setup, a use-after-free vulnerability occurs. This issue arises because a cached header pointer (`hdr`) is not reloaded after `pskb_may_pull()` potentially reallocates the packet buffer, leading to `hdr` pointing to freed memory. A remote attacker could exploit this to trigger a kernel crash, resulting in a denial of service."], "name": "CVE-2026-89555", "package_state": [{"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Fix deferred", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-09-11T19:44:28Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89555\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89555\nhttps://git.kernel.org/stable/c/29e63b8d9fc150cc191b1c6eb7e16e1247e1b650\nhttps://git.kernel.org/stable/c/49d38c1b4390412f8950d33dfaee0ccbd17beb81\nhttps://git.kernel.org/stable/c/d82b90a38c2ca8a0694428eab0e9551c23f2447d\nhttps://git.kernel.org/stable/c/fed638a248116b8a249bd4202d28e5934bdc65ad"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9f427a0e474a67b454420c131709600d44850486,fed638a248116b8a249bd4202d28e5934bdc65ad)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9f427a0e474a67b454420c131709600d44850486,d82b90a38c2ca8a0694428eab0e9551c23f2447d)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9f427a0e474a67b454420c131709600d44850486,49d38c1b4390412f8950d33dfaee0ccbd17beb81)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[9f427a0e474a67b454420c131709600d44850486,29e63b8d9fc150cc191b1c6eb7e16e1247e1b650)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "ad864d9fce0ec56cc8f6afe5c6a0e6d7f484b9eb"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[4.9.8,4.10)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "4.10"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,4.10)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.109,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.50,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.4,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-12T03:30:08.481685+00:00", "updated": "2026-09-15T22:00:17.649732+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}