SUNRPC: Bound-check xdr_buf_to_bvec() stores before writing

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72217
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:21:40 UTC
Updated2026-08-17 06:18:22 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.006260000 probability, percentile 0.470850000 (date 2026-08-17)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 2eb2b93581813b74c7174961126f6ec38eadb5a7 4a1148f2739d5089c3ca8ae2e9d1053e219ab5df git Not specified
CNA Linux Linux affected 2eb2b93581813b74c7174961126f6ec38eadb5a7 6029e711a818bf34d6c4b90cafee24f3afffa110 git Not specified
CNA Linux Linux affected 2eb2b93581813b74c7174961126f6ec38eadb5a7 69e18135e2a004a79505451dbef07314ea16e1eb git Not specified
CNA Linux Linux affected 2eb2b93581813b74c7174961126f6ec38eadb5a7 98414b42530af65cb984ffc12685096a3b5e179a git Not specified
CNA Linux Linux affected 2eb2b93581813b74c7174961126f6ec38eadb5a7 42f5b80dda6b86e424054baf1475df686c403d5c git Not specified
CNA Linux Linux affected 6.6 Not specified
CNA Linux Linux unaffected 6.6 semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/69e18135e2a004a79505451dbef07314ea16e1eb 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/98414b42530af65cb984ffc12685096a3b5e179a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/42f5b80dda6b86e424054baf1475df686c403d5c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6029e711a818bf34d6c4b90cafee24f3afffa110 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4a1148f2739d5089c3ca8ae2e9d1053e219ab5df 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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