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clsact: Fix use-after-free in init/destroy rollback asymmetry

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-23413

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-23413

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
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Fixed versions
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Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "230bb13650b0f186f540500fd5f5f7096a822a2a",
        "lessThan": "a73d95b57bf9faebdfed591bcb7ed9292062a84c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1cb6f0bae50441f4b4b32a28315853b279c7404e",
        "lessThan": "37bef86e5428d59f70a4da82b80f9a8f252fecbe",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1cb6f0bae50441f4b4b32a28315853b279c7404e",
        "lessThan": "4c9af67f99aa3e51b522c54968ab3ac8272be41c",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1cb6f0bae50441f4b4b32a28315853b279c7404e",
        "lessThan": "0509b762bc5e8ea7b8391130730c6d8502fc6e69",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "1cb6f0bae50441f4b4b32a28315853b279c7404e",
        "lessThan": "a0671125d4f55e1e98d9bde8a0b671941987e208",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "f61ecf1bd5b562ebfd7d430ccb31619857e80857",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "6.6.41",
        "lessThan": "6.6.130",
        "versionType": "semver"
      },
      {
        "status": "affected",
        "version": "6.9.10",
        "lessThan": "6.10",
        "versionType": "semver"
      }
    ],
    "programFiles": [
      "include/net/sch_generic.h",
      "net/sched/sch_ingress.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.10"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.10",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.130",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.78",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.20",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "6.19.10",
        "versionType": "semver",
        "lessThanOrEqual": "6.19.*"
      },
      {
        "status": "unaffected",
        "version": "7.0",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "include/net/sch_generic.h",
      "net/sched/sch_ingress.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-23413

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#39845 · Revision 1
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Publisher date
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