{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23413", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:46.014Z", "datePublished": "2026-04-02T11:40:54.384Z", "dateUpdated": "2026-08-05T12:21:33.571Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:21:33.571Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nclsact: Fix use-after-free in init/destroy rollback asymmetry\n\nFix a use-after-free in the clsact qdisc upon init/destroy rollback asymmetry.\nThe latter is achieved by first fully initializing a clsact instance, and\nthen in a second step having a replacement failure for the new clsact qdisc\ninstance. clsact_init() initializes ingress first and then takes care of the\negress part. This can fail midway, for example, via tcf_block_get_ext(). Upon\nfailure, the kernel will trigger the clsact_destroy() callback.\n\nCommit 1cb6f0bae504 (\"bpf: Fix too early release of tcx_entry\") details the\nway how the transition is happening. If tcf_block_get_ext on the q->ingress_block\nends up failing, we took the tcx_miniq_inc reference count on the ingress\nside, but not yet on the egress side. clsact_destroy() tests whether the\n{ingress,egress}_entry was non-NULL. However, even in midway failure on the\nreplacement, both are in fact non-NULL with a valid egress_entry from the\nprevious clsact instance.\n\nWhat we really need to test for is whether the qdisc instance-specific ingress\nor egress side previously got initialized. This adds a small helper for checking\nthe miniq initialization called mini_qdisc_pair_inited, and utilizes that upon\nclsact_destroy() in order to fix the use-after-free scenario. Convert the\ningress_destroy() side as well so both are consistent to each other." } ], "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 - The vulnerable `clsact` qdisc init/destroy path is reached through local rtnetlink `RTM_NEWQDISC` traffic, not by remote packets directly.\nAC:L - The failure path is attacker-controlled by creating/replacing `clsact` with shared block indexes so `tcf_block_get_ext()` fails during rollback; no uncontrollable race is required.\nPR:L - `RTM_NEWQDISC` requires `CAP_NET_ADMIN` in the target network namespace, and `tc`/qdisc operations are reachable by an unprivileged user via user+network namespaces.\nUI:N - After local access, exploitation only requires issuing crafted netlink/qdisc operations and does not require victim interaction.\nS:U - The bug is a standard kernel memory corruption issue within the same kernel security authority, not a VM or hardware isolation boundary escape.\nC:H - The bug is a use-after-free of `tcx_entry` state reachable through old `clsact` miniq callbacks, and UAF memory reuse can provide kernel memory disclosure primitives.\nI:H - The stale miniq pointer can lead to writes through freed/reallocated kernel memory, making control-flow or kernel data corruption defensible.\nA:H - The same UAF can be triggered into kernel crashes/oopses during qdisc/filter cleanup or callback paths, causing high availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/sch_generic.h", "net/sched/sch_ingress.c" ], "versions": [ { "version": "230bb13650b0f186f540500fd5f5f7096a822a2a", "lessThan": "a73d95b57bf9faebdfed591bcb7ed9292062a84c", "status": "affected", "versionType": "git" }, { "version": "1cb6f0bae50441f4b4b32a28315853b279c7404e", "lessThan": "37bef86e5428d59f70a4da82b80f9a8f252fecbe", "status": "affected", "versionType": "git" }, { "version": "1cb6f0bae50441f4b4b32a28315853b279c7404e", "lessThan": "4c9af67f99aa3e51b522c54968ab3ac8272be41c", "status": "affected", "versionType": "git" }, { "version": "1cb6f0bae50441f4b4b32a28315853b279c7404e", "lessThan": "0509b762bc5e8ea7b8391130730c6d8502fc6e69", "status": "affected", "versionType": "git" }, { "version": "1cb6f0bae50441f4b4b32a28315853b279c7404e", "lessThan": "a0671125d4f55e1e98d9bde8a0b671941987e208", "status": "affected", "versionType": "git" }, { "version": "f61ecf1bd5b562ebfd7d430ccb31619857e80857", "status": "affected", "versionType": "git" }, { "version": "6.6.41", "lessThan": "6.6.130", "status": "affected", "versionType": "semver" }, { "version": "6.9.10", "lessThan": "6.10", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/sch_generic.h", "net/sched/sch_ingress.c" ], "versions": [ { "version": "6.10", "status": "affected" }, { "version": "0", "lessThan": "6.10", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.130", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.78", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.20", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.10", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "6.6.41", "versionEndExcluding": "6.6.130" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.12.78" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.18.20" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "6.19.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.10", "versionEndExcluding": "7.0" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9.10" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a73d95b57bf9faebdfed591bcb7ed9292062a84c" }, { "url": "https://git.kernel.org/stable/c/37bef86e5428d59f70a4da82b80f9a8f252fecbe" }, { "url": "https://git.kernel.org/stable/c/4c9af67f99aa3e51b522c54968ab3ac8272be41c" }, { "url": "https://git.kernel.org/stable/c/0509b762bc5e8ea7b8391130730c6d8502fc6e69" }, { "url": "https://git.kernel.org/stable/c/a0671125d4f55e1e98d9bde8a0b671941987e208" } ], "title": "clsact: Fix use-after-free in init/destroy rollback asymmetry", "x_generator": { "engine": "bippy-1.2.0" } } } }