nfs: use nfsi->rwsem to protect traversal of the file lock list

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72472
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:22:21 UTC
Updated2026-08-17 06:19:15 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: nfs: use nfsi->rwsem to protect traversal of the file lock list Lingfeng identified a bug and suggested two solutions, but both appear to have issues. Generally, we cannot release flc_lock while iterating over the file lock list to avoid use-after-free (UAF) problems with file locks. However, functions like nfs_delegation_claim_locks and nfs4_reclaim_locks cannot adhere to this rule because recover_lock or nfs4_lock_delegation_recall may take a long time. To resolve this, NFS switches to using nfsi->rwsem for the same protection, and nfs_reclaim_locks follows this approach. Although nfs_delegation_claim_locks uses so_delegreturn_mutex instead, this is inadequate since a single inode can have multiple nfs4_state instances. Therefore, the fix is to also use nfsi->rwsem in this case. Furthermore, after commit c69899a17ca4 ("NFSv4: Update of VFS byte range lock must be atomic with the stateid update"), the functions nfs4_locku_done and nfs4_lock_done also break this rule because they call locks_lock_inode_wait without holding nfsi->rwsem. Simply adding this protection could cause many deadlocks, so instead, the call to locks_lock_inode_wait is moved into _nfs4_proc_setlk. Regarding the bug fixed by commit c69899a17ca4 ("NFSv4: Update of VFS byte range lock must be atomic with the stateid update"), it has been resolved after commit 0460253913e5 ("NFSv4: nfs4_do_open() is incorrectly triggering state recovery") because all slots are drained before calling nfs4_do_reclaim, which prevents concurrent stateid changes along this path. Also, nfs_delegation_claim_locks does not cause this concurrency either since when _nfs4_proc_setlk is called with NFS_DELEGATED_STATE, no RPC is sent, so nfs4_lock_done is not called. Therefore, nfs4_lock_delegation_recall from nfs_delegation_claim_locks is the first time the stateid is set.

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: 0.006440000 probability, percentile 0.479010000 (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 c69899a17ca4836230720e65493942d9582a0424 1cda95bf2e9c0e6b63545b7565fe4a1e474322f4 git Not specified
CNA Linux Linux affected c69899a17ca4836230720e65493942d9582a0424 f161ef7b0dd2f51fdb002ba4a4e9bf0ee7409218 git Not specified
CNA Linux Linux affected c69899a17ca4836230720e65493942d9582a0424 e68035178e65e2b3aa386ce61202ff33724ae418 git Not specified
CNA Linux Linux affected c69899a17ca4836230720e65493942d9582a0424 4837fb36219e6c08b666bc31a86841bad8526358 git Not specified
CNA Linux Linux affected 4.0 Not specified
CNA Linux Linux unaffected 4.0 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/e68035178e65e2b3aa386ce61202ff33724ae418 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f161ef7b0dd2f51fdb002ba4a4e9bf0ee7409218 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/1cda95bf2e9c0e6b63545b7565fe4a1e474322f4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/4837fb36219e6c08b666bc31a86841bad8526358 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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