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CVE-2026-72461 (GCVE-0-2026-72461)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:57 – Updated: 2026-08-17 05:44
VLAI
Title
apparmor: fix refcount leak when updating the sk_ctx
Summary
In the Linux kernel, the following vulnerability has been resolved: apparmor: fix refcount leak when updating the sk_ctx Currently update_sk_ctx() transfers the plabel reference, unfortunately it is also unconditionally put in the caller. Ideally we would make the caller conditionally put the reference based on whether it was transferred but for now just fix the bug by getting a reference.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 88fec3526e84123997ecebd6bb6778eb4ce779b7 , < 045dbe89ac31709abd73390d0805d52fece7ef39 (git)
Affected: 88fec3526e84123997ecebd6bb6778eb4ce779b7 , < b8642f1478982a97ca2eb59f70f631a9de42ae11 (git)
Affected: 88fec3526e84123997ecebd6bb6778eb4ce779b7 , < 6d25e7b47616cb2db43351210929c8f19dc305a3 (git)
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Linux Linux Affected: 6.17
Unaffected: 0 , < 6.17 (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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              "value": "AV:L - The bug is reached only through local Unix-domain socket operations (sendmsg/recvmsg SCM_RIGHTS fd passing, exec file inheritance, or socket file permission revalidation) that invoke AppArmor LSM hooks; it is not reachable via remote network protocols.\nAC:L - An attacker can reliably trigger update_sk_ctx() by creating connected abstract/anonymous AF_UNIX sockets and repeatedly passing the fd across AppArmor confinement boundaries, controlling both endpoints and syscall timing without external race luck.\nPR:L - Only a local unprivileged process subject to AppArmor confinement is required (typical Ubuntu snap/container workloads); no init-namespace root, CAP_MAC_ADMIN, or policy-loading privileges are needed to exercise unix socket mediation.\nUI:N - Exploitation is driven entirely by attacker-initiated syscalls and automated fd-receive paths; no additional voluntary action from another human user is required beyond normal daemon recvmsg behavior.\nS:U - The flaw corrupts AppArmor label refcounting in the host kernel heap; impact stays within the same kernel security authority and does not by itself cross VM, IOMMU, or container hypervisor boundaries.\nC:H - update_sk_ctx() stored plabel in peer_lastupdate without aa_get_label() while the caller aa_put_label(plabel), allowing aa_label objects to be freed while still referenced, creating a heap use-after-free readable via later pointer comparisons and teardown.\nI:H - Use-after-free/double-free of aa_label structures on socket teardown enables attacker-influenced heap reuse of label objects, which can be leveraged for arbitrary kernel memory corruption and local privilege escalation.\nA:H - Incorrect refcounting causes premature aa_label free and an extra aa_put_label() at sk teardown, provoking refcount underflow, kernel oops, or panic on AppArmor-enabled systems under repeated unix fd passing."
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72461",
    "datePublished": "2026-08-15T05:57:06.042Z",
    "dateReserved": "2026-08-09T03:40:39.933Z",
    "dateUpdated": "2026-08-17T05:44:27.397Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T07:27:33+00:00",
      "cve": "CVE-2026-72461",
      "id": "CVE-2026-72461",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: apparmor: fix refcount leak when updating the sk_ctx",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72461.json",
      "version": "3"
    }
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.