CVE-2026-99167

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-99167", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.398Z", "datePublished": "2026-10-28T10:35:18.850Z", "dateUpdated": "2026-10-31T12:44:30.175Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-31T12:44:30.175Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fix use-after-free in __tcf_action_put()\n\n__tcf_action_put() decrements the reference count before decrementing the\nbinding count. Another thread can free the action between these operations,\ncausing the binding-count update to access freed memory. KASAN reports it\nas:\n\n BUG: KASAN: slab-use-after-free in __tcf_action_put+0x327/0x340\n Write of size 4 at addr ff11000000d46420 by task tc-put-pause/64\n\nHold the action IDR mutex across both counter updates and IDR removal,\nkeeping cleanup outside the lock."}], "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 - An attacker reaches the patched __tcf_action_put() through local NETLINK_ROUTE messages: sendmsg() -> rtnetlink_rcv_msg() -> tc_new_tfilter()/tc_del_tfilter() -> tcf_action_destroy(). No received network packet supplies the action release operation.\nAC:L - RTM_NEWTFILTER and RTM_DELTFILTER are unlocked for flower on clsact/ingress; the attacker can race a failing bind request's tcf_action_destroy() against deletion cleanup of the same indexed action. One put takes tcfa_refcnt 2->1 before tcfa_bindcnt while the other takes 1->0 and frees it, so both sides are attacker-controlled.\nPR:L - rtnetlink_rcv_msg() requires netlink_net_capable(skb, CAP_NET_ADMIN), but checks the user namespace owning the socket's network namespace. An unprivileged user can use unshare(CLONE_NEWUSER|CLONE_NEWNET) to obtain that capability in the new namespace and configure its clsact/flower objects.\nUI:N - After creating the namespace and TC objects, the attacker alone sends the racing RTM_NEWTFILTER and RTM_DELTFILTER messages; no victim action is required.\nS:U - __tcf_action_put() corrupts memory in the same host kernel that processes and authorizes the NETLINK_ROUTE requests; exploitation does not cross a VM or IOMMU security boundary.\nC:H - After free_tcf() queues p for reclamation through kfree_rcu(), the stale path retains p and later accesses the reclaimed tcfa_bindcnt slot. Action-heap grooming can turn corruption of a replacement object into control-flow execution and arbitrary kernel-memory disclosure.\nI:H - atomic_dec(&p->tcfa_bindcnt) performs a 32-bit write after the tc_action allocation has been reclaimed; spraying a same-cache replacement can corrupt its refcount, length, or control data and enable kernel code execution or arbitrary modification.\nA:H - The reported KASAN slab-use-after-free is the stale atomic_dec() write in __tcf_action_put(); corrupting the replacement object can cause an oops or panic, and the attacker can repeatedly attempt the netlink race."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sched/act_api.c"], "versions": [{"version": "16af6067392c40e454e49eec834843ab03643d96", "lessThan": "4d83a3fc03bc595dd39b79ad61288738fbb1f2ba", "status": "affected", "versionType": "git"}, {"version": "16af6067392c40e454e49eec834843ab03643d96", "lessThan": "fd01abed2568209f7daaf60e5ee68ae4a4744f48", "status": "affected", "versionType": "git"}, {"version": "16af6067392c40e454e49eec834843ab03643d96", "lessThan": "fcc7d734ceccfab8ec3398c5b34f8e775d459507", "status": "affected", "versionType": "git"}, {"version": "16af6067392c40e454e49eec834843ab03643d96", "lessThan": "fde33eb9955d819af282d5f5e84684eaec248291", "status": "affected", "versionType": "git"}, {"version": "16af6067392c40e454e49eec834843ab03643d96", "lessThan": "969ad6f2b266f383b44194d50d15631969b26222", "status": "affected", "versionType": "git"}, {"version": "16af6067392c40e454e49eec834843ab03643d96", "lessThan": "2465d27ef90de9105c2bffb6c35f8ce08918e642", "status": "affected", "versionType": "git"}, {"version": "16af6067392c40e454e49eec834843ab03643d96", "lessThan": "2e012e431aa271ef3c84206f48854f539c03bff0", "status": "affected", "versionType": "git"}, {"version": "16af6067392c40e454e49eec834843ab03643d96", "lessThan": "7b16eb911091aae237a8673da94e4dfb9cd21d54", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sched/act_api.c"], "versions": [{"version": "4.19", "status": "affected"}, {"version": "0", "lessThan": "4.19", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.273", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.224", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.161", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.115", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.59", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.13", "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": "4.19", "versionEndExcluding": "5.10.273"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "5.15.224"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.6.161"}, {"vulnerable": true, "criteria": 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"https://git.kernel.org/stable/c/969ad6f2b266f383b44194d50d15631969b26222"}, {"url": "https://git.kernel.org/stable/c/2465d27ef90de9105c2bffb6c35f8ce08918e642"}, {"url": "https://git.kernel.org/stable/c/2e012e431aa271ef3c84206f48854f539c03bff0"}, {"url": "https://git.kernel.org/stable/c/7b16eb911091aae237a8673da94e4dfb9cd21d54"}], "title": "net/sched: fix use-after-free in __tcf_action_put()", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/sched/act_api.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "4d83a3fc03bc595dd39b79ad61288738fbb1f2ba", "status": "affected", "version": "16af6067392c40e454e49eec834843ab03643d96", "versionType": "git"}, {"lessThan": "fd01abed2568209f7daaf60e5ee68ae4a4744f48", "status": "affected", "version": "16af6067392c40e454e49eec834843ab03643d96", "versionType": "git"}, {"lessThan": "fcc7d734ceccfab8ec3398c5b34f8e775d459507", "status": "affected", "version": "16af6067392c40e454e49eec834843ab03643d96", "versionType": "git"}, {"lessThan": "fde33eb9955d819af282d5f5e84684eaec248291", "status": "affected", "version": "16af6067392c40e454e49eec834843ab03643d96", "versionType": "git"}, {"lessThan": "969ad6f2b266f383b44194d50d15631969b26222", "status": "affected", "version": "16af6067392c40e454e49eec834843ab03643d96", "versionType": "git"}, {"lessThan": "2465d27ef90de9105c2bffb6c35f8ce08918e642", "status": "affected", "version": "16af6067392c40e454e49eec834843ab03643d96", "versionType": "git"}, {"lessThan": "2e012e431aa271ef3c84206f48854f539c03bff0", "status": "affected", "version": "16af6067392c40e454e49eec834843ab03643d96", "versionType": "git"}, {"lessThan": "7b16eb911091aae237a8673da94e4dfb9cd21d54", "status": "affected", "version": "16af6067392c40e454e49eec834843ab03643d96", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/sched/act_api.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "4.19"}, {"lessThan": "4.19", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.273", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.224", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.161", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.115", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.59", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.13", "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\nnet/sched: fix use-after-free in __tcf_action_put()\n\n__tcf_action_put() decrements the reference count before decrementing the\nbinding count. Another thread can free the action between these operations,\ncausing the binding-count update to access freed memory. KASAN reports it\nas:\n\n BUG: KASAN: slab-use-after-free in __tcf_action_put+0x327/0x340\n Write of size 4 at addr ff11000000d46420 by task tc-put-pause/64\n\nHold the action IDR mutex across both counter updates and IDR removal,\nkeeping cleanup outside the lock."}], "id": "CVE-2026-99167", "lastModified": "2026-10-31T13:17:58.417", "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"}]}, "published": "2026-10-28T11:17:37.173", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2465d27ef90de9105c2bffb6c35f8ce08918e642"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2e012e431aa271ef3c84206f48854f539c03bff0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/4d83a3fc03bc595dd39b79ad61288738fbb1f2ba"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7b16eb911091aae237a8673da94e4dfb9cd21d54"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/969ad6f2b266f383b44194d50d15631969b26222"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fcc7d734ceccfab8ec3398c5b34f8e775d459507"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fd01abed2568209f7daaf60e5ee68ae4a4744f48"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/fde33eb9955d819af282d5f5e84684eaec248291"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: net/sched: fix use-after-free in __tcf_action_put()", "id": "2562676", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2562676"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.8", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nnet/sched: fix use-after-free in __tcf_action_put()\n__tcf_action_put() decrements the reference count before decrementing the\nbinding count. Another thread can free the action between these operations,\ncausing the binding-count update to access freed memory. KASAN reports it\nas:\nBUG: KASAN: slab-use-after-free in __tcf_action_put+0x327/0x340\nWrite of size 4 at addr ff11000000d46420 by task tc-put-pause/64\nHold the action IDR mutex across both counter updates and IDR removal,\nkeeping cleanup outside the lock.", "A flaw was found in the Linux kernel's traffic control (net/sched) subsystem. Due to improper synchronization in the __tcf_action_put() function, reference and binding counts are updated out of sequence during action cleanup, allowing memory to be released while still being accessed. A local attacker could exploit this race condition to cause a use-after-free error, potentially resulting in local privilege escalation or a Denial of Service (DoS) via a system crash."], "name": "CVE-2026-99167", "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": "Affected", "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"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-28T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-99167\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-99167\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-99167.mbox"], "threat_severity": "Important"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[16af6067392c40e454e49eec834843ab03643d96,2465d27ef90de9105c2bffb6c35f8ce08918e642)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[16af6067392c40e454e49eec834843ab03643d96,2e012e431aa271ef3c84206f48854f539c03bff0)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[16af6067392c40e454e49eec834843ab03643d96,7b16eb911091aae237a8673da94e4dfb9cd21d54)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.19"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,4.19)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.18.59,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2.13,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[16af6067392c40e454e49eec834843ab03643d96,2465d27ef90de9105c2bffb6c35f8ce08918e642)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[16af6067392c40e454e49eec834843ab03643d96,2e012e431aa271ef3c84206f48854f539c03bff0)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[16af6067392c40e454e49eec834843ab03643d96,7b16eb911091aae237a8673da94e4dfb9cd21d54)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "4.19"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,4.19)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.18.59,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2.13,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-10-28T12:45:16.180106+00:00", "updated": "2026-10-29T18:45:14.338041+00:00", "vendors": ["linux", "linux$PRODUCT$linux", "linux$PRODUCT$linux_kernel"]}