CVE-2026-63800 (GCVE-0-2026-63800)
Vulnerability from cvelistv5
Published
2026-07-19 12:02
Modified
2026-08-17 04:51
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
pNFS: Fix use-after-free in pnfs_update_layout()
When hitting the NFS_LAYOUT_RETURN branch in pnfs_update_layout(),
the code calls pnfs_prepare_to_retry_layoutget(lo). If it succeeds,
pnfs_put_layout_hdr(lo) is called before trace_pnfs_update_layout(),
which still references 'lo'. This results in a use-after-free when the
tracepoint accesses lo's fields.
Fix this by moving the tracepoint call before pnfs_put_layout_hdr(lo).
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 06f58dbc49a23c99e5c0f246879ed16667f7bf8f Version: 2c8d5fc37fe2384a9bdb6965443ab9224d46f704 Version: 2c8d5fc37fe2384a9bdb6965443ab9224d46f704 Version: 2c8d5fc37fe2384a9bdb6965443ab9224d46f704 Version: 2c8d5fc37fe2384a9bdb6965443ab9224d46f704 Version: 2c8d5fc37fe2384a9bdb6965443ab9224d46f704 Version: 2c8d5fc37fe2384a9bdb6965443ab9224d46f704 Version: 2c8d5fc37fe2384a9bdb6965443ab9224d46f704 Version: aa2399f55eff4ec78330bb6fe55f9df53e5cae0c Version: 5.10.9 ≤ Version: 5.4.91 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/nfs/pnfs.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"status": "affected",
"version": "06f58dbc49a23c99e5c0f246879ed16667f7bf8f",
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},
{
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"version": "2c8d5fc37fe2384a9bdb6965443ab9224d46f704",
"versionType": "git"
},
{
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"status": "affected",
"version": "2c8d5fc37fe2384a9bdb6965443ab9224d46f704",
"versionType": "git"
},
{
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{
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"status": "affected",
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"status": "affected",
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"versionType": "git"
},
{
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"status": "affected",
"version": "5.10.9",
"versionType": "semver"
},
{
"lessThan": "5.5",
"status": "affected",
"version": "5.4.91",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/nfs/pnfs.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.11"
},
{
"lessThan": "5.11",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.260",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.211",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.177",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.144",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.95",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.38",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.260",
"versionStartIncluding": "5.10.9",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.211",
"versionStartIncluding": "5.11",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.177",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.144",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.95",
"versionStartIncluding": "5.11",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.38",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.3",
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{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.4.91",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\npNFS: Fix use-after-free in pnfs_update_layout()\n\nWhen hitting the NFS_LAYOUT_RETURN branch in pnfs_update_layout(),\nthe code calls pnfs_prepare_to_retry_layoutget(lo). If it succeeds,\npnfs_put_layout_hdr(lo) is called before trace_pnfs_update_layout(),\nwhich still references \u0027lo\u0027. This results in a use-after-free when the\ntracepoint accesses lo\u0027s fields.\n\nFix this by moving the tracepoint call before pnfs_put_layout_hdr(lo)."
}
],
"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 - A compromised or malicious pNFS NFSv4.1+ metadata server can send CB_LAYOUTRECALL callbacks over the NFSv4 backchannel to force NFS_LAYOUT_RETURN while client file I/O reaches pnfs_update_layout(), exploiting the client from the network in typical enterprise/HPC pNFS deployments.\nAC:L - The attacker controls both sides of the race by issuing layout recalls from the server and driving or waiting for concurrent read/write I/O on the mounted pNFS share; no conditions beyond attacker influence are required once a pNFS session exists.\nPR:N - Exploitation requires no local privileges on the victim client\u2014a remote NFS server with an established pNFS session can trigger the layoutreturn/retry path while any client process performs permitted file I/O on the mount.\nUI:N - No interactive victim action is needed during exploitation; automated workloads, daemons, or batch jobs performing routine I/O on an existing pNFS mount are sufficient to hit the vulnerable code path.\nS:U - The use-after-free corrupts kernel heap memory within the same kernel security domain and does not cross a VM, container, or IOMMU boundary on its own.\nC:H - The tracepoint reads freed pnfs_layout_hdr fields (plh_stateid seqid and hash) after pnfs_put_layout_hdr() drops the final reference, giving an attacker-controlled use-after-free read primitive over kernel heap memory.\nI:H - Use-after-free on a refcounted kernel layout object enables heap grooming and further memory corruption for arbitrary kernel writes or control-flow hijacking, not merely a bounded fault.\nA:H - Dereferencing a freed pnfs_layout_hdr in kernel context can cause an oops or panic, and use-after-free corruption reliably threatens system availability even when full exploitation is not attempted."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T04:51:05.578Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/4ad8b9a85dbf57ca532ee9e65ad7e6498bfbbf98"
},
{
"url": "https://git.kernel.org/stable/c/1f24b8302c77dcaf79c64c073877a3b9f4dd25d2"
},
{
"url": "https://git.kernel.org/stable/c/9c0fb5c09ae5bd68dc0038692af8127029cb0385"
},
{
"url": "https://git.kernel.org/stable/c/7e37e9b3e82ade881e1798e2f4fcc54aff7793c1"
},
{
"url": "https://git.kernel.org/stable/c/2883ddd7542b4437a2ab4908fe2773f690e20889"
},
{
"url": "https://git.kernel.org/stable/c/200e7637f4d6a1342987045eea72641524f909dc"
},
{
"url": "https://git.kernel.org/stable/c/9645aaf689aff57427ece3b9fa47d5b5399417f4"
},
{
"url": "https://git.kernel.org/stable/c/13e198a90ca4050f4bee8a3f23680389a6563ccc"
}
],
"title": "pNFS: Fix use-after-free in pnfs_update_layout()",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-63800",
"datePublished": "2026-07-19T12:02:06.897Z",
"dateReserved": "2026-07-19T07:54:57.013Z",
"dateUpdated": "2026-08-17T04:51:05.578Z",
"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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