SUNRPC: Bound-check xdr_buf_to_bvec() stores before writing
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In 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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.145, 6.12.97, 6.18.40, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet |
| Red Hat Enterprise Linux 6 | Affected | — |
Not affected: 3 products
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-72217
- 2026-10-03 Alias added: GHSA-jffc-255g-3gq9
- 2026-10-09 EPSS moved to the below the 50th percentile
- 2026-10-25 EPSS moved to the 50th–90th percentile
References
Other 5
- https://git.kernel.org/stable/c/4a1148f2739d5089c3ca8ae2e9d1053e219ab5df
- https://git.kernel.org/stable/c/6029e711a818bf34d6c4b90cafee24f3afffa110
- https://git.kernel.org/stable/c/69e18135e2a004a79505451dbef07314ea16e1eb
- https://git.kernel.org/stable/c/98414b42530af65cb984ffc12685096a3b5e179a
- https://git.kernel.org/stable/c/42f5b80dda6b86e424054baf1475df686c403d5c
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- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
Sources
- CVE-2026-72217 · CVE Program
- CVE-2026-72217 · NVD
- FIRST EPSS
- GHSA-jffc-255g-3gq9 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-72217 · Red Hat security data · CC BY 4.0
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