GHSA-5V8R-FJ78-FFG6
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33In the Linux kernel, the following vulnerability has been resolved:
lockd: Avoid hashing uninitialized bytes in nlm4svc_lookup_file()
file_hash() digests the first LOCKD_FH_HASH_SIZE bytes of nfs_fh.data when bucketing nlm_files[], independent of fh.size. Commit 3de744ee4e45 ("lockd: Use xdrgen XDR functions for the NLMv4 TEST procedure") set .pc_argzero to zero for the converted procedures and moved file-handle population into nlm4svc_lookup_file(), which copies only xdr_lock->fh.len bytes into lock->fh.data.
When an NLMv4 client presents a file handle shorter than LOCKD_FH_HASH_SIZE, bytes fh.len..31 retain whatever the argument buffer held from an earlier request. The same wire handle then hashes to different buckets across calls; nlm_lookup_file() misses the existing nlm_file entry, and lock-state lookups fail.
Zero only the tail bytes that file_hash() would otherwise consume. Handles of LOCKD_FH_HASH_SIZE or larger already populate every byte that file_hash() reads.
{
"affected": [],
"aliases": [
"CVE-2026-74315"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:22:31Z",
"severity": "CRITICAL"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nlockd: Avoid hashing uninitialized bytes in nlm4svc_lookup_file()\n\nfile_hash() digests the first LOCKD_FH_HASH_SIZE bytes of\nnfs_fh.data when bucketing nlm_files[], independent of fh.size.\nCommit 3de744ee4e45 (\"lockd: Use xdrgen XDR functions for the\nNLMv4 TEST procedure\") set .pc_argzero to zero for the converted\nprocedures and moved file-handle population into\nnlm4svc_lookup_file(), which copies only xdr_lock-\u003efh.len bytes\ninto lock-\u003efh.data.\n\nWhen an NLMv4 client presents a file handle shorter than\nLOCKD_FH_HASH_SIZE, bytes fh.len..31 retain whatever the argument\nbuffer held from an earlier request. The same wire handle then\nhashes to different buckets across calls; nlm_lookup_file() misses\nthe existing nlm_file entry, and lock-state lookups fail.\n\nZero only the tail bytes that file_hash() would otherwise consume.\nHandles of LOCKD_FH_HASH_SIZE or larger already populate every byte\nthat file_hash() reads.",
"id": "GHSA-5v8r-fj78-ffg6",
"modified": "2026-08-17T06:33:37Z",
"published": "2026-08-15T06:32:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74315"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/686c2434f9f16b87aeed18d76cc562df9f2695ab"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6e4c62caecf792e8a15ad9bc7f371e57c17e3302"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
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- 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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.