GHSA-JFFC-255G-3GQ9
Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33In the Linux kernel, the following vulnerability has been resolved:
SUNRPC: Bound-check xdr_buf_to_bvec() stores before writing
xdr_buf_to_bvec() writes a bio_vec into the caller's array before testing whether that slot is in range, and the head branch performs the store with no check at all. When the caller's budget is exactly used up, the next store lands one element past the end of the array. The overflow label returns count - 1, which masks the surplus store but cannot undo it.
rq_bvec, the array passed by nfsd_vfs_write(), is allocated to exactly rq_maxpages entries with no slack. The OOB store can land in adjacent slab memory; the bv_len and bv_offset fields written there are derived from client-supplied RPC payload sizes.
Move the in-range check ahead of the store in the head, page-loop, and tail branches. With the check at the top of each sequence, count is incremented only after a successful store, so the overflow label can return count directly.
{
"affected": [],
"aliases": [
"CVE-2026-72217"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-15T06:21:40Z",
"severity": "CRITICAL"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nSUNRPC: Bound-check xdr_buf_to_bvec() stores before writing\n\nxdr_buf_to_bvec() writes a bio_vec into the caller\u0027s array before\ntesting whether that slot is in range, and the head branch performs\nthe store with no check at all. When the caller\u0027s budget is exactly\nused up, the next store lands one element past the end of the array.\nThe overflow label returns count - 1, which masks the surplus store\nbut cannot undo it.\n\nrq_bvec, the array passed by nfsd_vfs_write(), is allocated to\nexactly rq_maxpages entries with no slack. The OOB store can land in\nadjacent slab memory; the bv_len and bv_offset fields written there\nare derived from client-supplied RPC payload sizes.\n\nMove the in-range check ahead of the store in the head, page-loop,\nand tail branches. With the check at the top of each sequence, count\nis incremented only after a successful store, so the overflow label\ncan return count directly.",
"id": "GHSA-jffc-255g-3gq9",
"modified": "2026-08-17T06:33:16Z",
"published": "2026-08-15T06:32:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72217"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/42f5b80dda6b86e424054baf1475df686c403d5c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4a1148f2739d5089c3ca8ae2e9d1053e219ab5df"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6029e711a818bf34d6c4b90cafee24f3afffa110"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/69e18135e2a004a79505451dbef07314ea16e1eb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/98414b42530af65cb984ffc12685096a3b5e179a"
}
],
"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.
- 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.
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.