CVE-2026-23413 (GCVE-0-2026-23413)

Vulnerability from cvelistv5 – Published: 2026-04-02 11:40 – Updated: 2026-10-19 18:35
VLAI
Title
clsact: Fix use-after-free in init/destroy rollback asymmetry
Summary
In the Linux kernel, the following vulnerability has been resolved: clsact: Fix use-after-free in init/destroy rollback asymmetry Fix a use-after-free in the clsact qdisc upon init/destroy rollback asymmetry. The latter is achieved by first fully initializing a clsact instance, and then in a second step having a replacement failure for the new clsact qdisc instance. clsact_init() initializes ingress first and then takes care of the egress part. This can fail midway, for example, via tcf_block_get_ext(). Upon failure, the kernel will trigger the clsact_destroy() callback. Commit 1cb6f0bae504 ("bpf: Fix too early release of tcx_entry") details the way how the transition is happening. If tcf_block_get_ext on the q->ingress_block ends up failing, we took the tcx_miniq_inc reference count on the ingress side, but not yet on the egress side. clsact_destroy() tests whether the {ingress,egress}_entry was non-NULL. However, even in midway failure on the replacement, both are in fact non-NULL with a valid egress_entry from the previous clsact instance. What we really need to test for is whether the qdisc instance-specific ingress or egress side previously got initialized. This adds a small helper for checking the miniq initialization called mini_qdisc_pair_inited, and utilizes that upon clsact_destroy() in order to fix the use-after-free scenario. Convert the ingress_destroy() side as well so both are consistent to each other.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-10-16 15:07 UTC
CWE
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6992 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 230bb13650b0f186f540500fd5f5f7096a822a2a , < a73d95b57bf9faebdfed591bcb7ed9292062a84c (git)
Affected: 1cb6f0bae50441f4b4b32a28315853b279c7404e , < 37bef86e5428d59f70a4da82b80f9a8f252fecbe (git)
Affected: 1cb6f0bae50441f4b4b32a28315853b279c7404e , < 4c9af67f99aa3e51b522c54968ab3ac8272be41c (git)
Affected: 1cb6f0bae50441f4b4b32a28315853b279c7404e , < 0509b762bc5e8ea7b8391130730c6d8502fc6e69 (git)
Affected: 1cb6f0bae50441f4b4b32a28315853b279c7404e , < a0671125d4f55e1e98d9bde8a0b671941987e208 (git)
Affected: f61ecf1bd5b562ebfd7d430ccb31619857e80857 (git)
Affected: 6.6.41 , < 6.6.130 (semver)
Affected: 6.9.10 , < 6.10 (semver)
guessed Create a notification for this product.
Linux Linux Affected: 6.10
Unaffected: 0 , < 6.10 (semver)
Unaffected: 6.6.130 , ≤ 6.6.* (semver)
Unaffected: 6.12.78 , ≤ 6.12.* (semver)
Unaffected: 6.18.20 , ≤ 6.18.* (semver)
Unaffected: 6.19.10 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: clsact: Fix use-after-free in init/destroy rollback asymmetry",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-23413.json",
      "version": "3"
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}



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