CVE-2026-72461 (GCVE-0-2026-72461)
Vulnerability from cvelistv5
Published
2026-08-15 05:57
Modified
2026-08-17 05:44
Severity ?
VLAI Severity ?
EPSS score ?
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.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"security/apparmor/af_unix.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"status": "affected",
"version": "88fec3526e84123997ecebd6bb6778eb4ce779b7",
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"versionType": "git"
},
{
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"status": "affected",
"version": "88fec3526e84123997ecebd6bb6778eb4ce779b7",
"versionType": "git"
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"vendor": "Linux",
"versions": [
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"version": "6.17"
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"version": "0",
"versionType": "semver"
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"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "7.1.5",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
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"nodes": [
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"vulnerable": true
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\napparmor: fix refcount leak when updating the sk_ctx\n\nCurrently update_sk_ctx() transfers the plabel reference, unfortunately\nit is also unconditionally put in the caller. Ideally we would make\nthe caller conditionally put the reference based on whether it was\ntransferred but for now just fix the bug by getting a reference."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"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."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:44:27.397Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"references": [
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"url": "https://git.kernel.org/stable/c/045dbe89ac31709abd73390d0805d52fece7ef39"
},
{
"url": "https://git.kernel.org/stable/c/b8642f1478982a97ca2eb59f70f631a9de42ae11"
},
{
"url": "https://git.kernel.org/stable/c/6d25e7b47616cb2db43351210929c8f19dc305a3"
}
],
"title": "apparmor: fix refcount leak when updating the sk_ctx",
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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"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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