CVE-2026-72220 (GCVE-0-2026-72220)
Vulnerability from cvelistv5
Published
2026-08-15 05:54
Modified
2026-08-17 05:41
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
sunrpc: harden rq_procinfo lifecycle to prevent double-free
The svc_release_rqst() function executes the callback inside
rqstp->rq_procinfo->pc_release. However, if a worker thread begins
processing a new request and encounters an early error path (e.g.,
unsupported protocol, short frame, or bad auth) before a valid
rq_procinfo is installed, a stale release hook can be re-triggered
against reused state from the previous RPC, resulting in a double-free
or use-after-free vulnerability.
Harden the lifecycle of rq_procinfo by:
1. Ensuring svc_release_rqst() always clears rq_procinfo after the
optional pc_release() call, regardless of whether the hook exists.
2. Explicitly clearing rq_procinfo at request entry in svc_process()
before any early decode or drop paths.
3. Ensuring svc_process_bc() does the same at backchannel entry.
This guarantees that error flows will not encounter a non-NULL stale
rq_procinfo pointer when there is nothing to release.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/sunrpc/svc.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"versionType": "git"
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{
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"status": "affected",
"version": "d9adbb6e10bf7d4223d3d521ede1b2052903bc5e",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/sunrpc/svc.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.18"
},
{
"lessThan": "6.18",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"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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"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.40",
"versionStartIncluding": "6.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"negate": false,
"operator": "OR"
}
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}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: harden rq_procinfo lifecycle to prevent double-free\n\nThe svc_release_rqst() function executes the callback inside\nrqstp-\u003erq_procinfo-\u003epc_release. However, if a worker thread begins\nprocessing a new request and encounters an early error path (e.g.,\nunsupported protocol, short frame, or bad auth) before a valid\nrq_procinfo is installed, a stale release hook can be re-triggered\nagainst reused state from the previous RPC, resulting in a double-free\nor use-after-free vulnerability.\n\nHarden the lifecycle of rq_procinfo by:\n1. Ensuring svc_release_rqst() always clears rq_procinfo after the\n optional pc_release() call, regardless of whether the hook exists.\n2. Explicitly clearing rq_procinfo at request entry in svc_process()\n before any early decode or drop paths.\n3. Ensuring svc_process_bc() does the same at backchannel entry.\n\nThis guarantees that error flows will not encounter a non-NULL stale\nrq_procinfo pointer when there is nothing to release."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - The flaw is in server-side SUNRPC request handling reached from remote RPC over TCP/UDP/RDMA transports used by nfsd and lockd (svc_recv\u2192svc_handle_xprt\u2192svc_process), exploitable by sending crafted ONC/RPC packets to listening NFS/NLM ports.\nAC:L - An attacker controls the RPC sequence and timing (valid request then malformed/short/bad-auth/bad-prog packet on the same pooled worker) to reliably re-trigger a stale pc_release without depending on uncontrollable layout or victim state.\nPR:N - Trigger paths include pre-authentication failures (garbage credentials, unknown program/version, short frames) that still call svc_release_rqst; stale rq_procinfo can be left by any prior RPC on the same worker, so no attacker credentials are required.\nUI:N - Exploitation requires only network RPC traffic to an already-running NFS/NLM server; no end-user actions such as mounting a share or opening files are needed beyond normal server exposure.\nS:U - Impact is kernel heap corruption and privilege escalation within the host kernel context; it does not inherently cross a VM, container, or IOMMU security boundary to another authority.\nC:H - The bug is an explicit double-free/use-after-free of per-request NFS release state (e.g. nfsd4_release_compoundargs kfree/vfree chains and fh_put paths), enabling arbitrary kernel memory disclosure when exploited.\nI:H - Re-invoking pc_release on reused svc_rqst buffers corrupts heap metadata and object lifetimes, providing a standard kernel double-free/UAF primitive suitable for arbitrary write and code execution.\nA:H - Repeated or mistimed pc_release calls can immediately panic the kernel via SLUB double-free detection, oops, or wedged nfsd worker threads, causing complete loss of availability on NFS-serving systems."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:41:41.598Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/66014ab165cb01bfef5836939412a8ef98d5d5ff"
},
{
"url": "https://git.kernel.org/stable/c/31ba490c02d476a5e4f90b8845932ac9db8aa71b"
},
{
"url": "https://git.kernel.org/stable/c/18d216788bef06332ff8901670ecf1ed8f6eb614"
}
],
"title": "sunrpc: harden rq_procinfo lifecycle to prevent double-free",
"x_generator": {
"engine": "bippy-1.2.0"
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}
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72220",
"datePublished": "2026-08-15T05:54:13.800Z",
"dateReserved": "2026-08-09T03:40:39.913Z",
"dateUpdated": "2026-08-17T05:41:41.598Z",
"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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