{"id":"CVE-2026-72472","title":"nfs: use nfsi->rwsem to protect traversal of the file lock list","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfs: use nfsi->rwsem to protect traversal of the file lock list\n\nLingfeng identified a bug and suggested two solutions, but both appear\nto have issues.\n\nGenerally, we c…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= c69899a17ca4836230720e65493942d9582a0424 < 1cda95bf2e9c0e6b63545b7565fe4a1e474322f4","Linux >= c69899a17ca4836230720e65493942d9582a0424 < f161ef7b0dd2f51fdb002ba4a4e9bf0ee7409218","Linux >= c69899a17ca4836230720e65493942d9582a0424 < e68035178e65e2b3aa386ce61202ff33724ae418","Linux >= c69899a17ca4836230720e65493942d9582a0424 < 4837fb36219e6c08b666bc31a86841bad8526358","Linux 4.0"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"total","timestamp":"2026-10-16T18:50:31.105592Z"},"published":"2026-08-15","updated":"2026-10-16","sourceUpdated":"2026-10-16T18:55:25.590Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-72472","references":[{"url":"https://git.kernel.org/stable/c/1cda95bf2e9c0e6b63545b7565fe4a1e474322f4"},{"url":"https://git.kernel.org/stable/c/f161ef7b0dd2f51fdb002ba4a4e9bf0ee7409218"},{"url":"https://git.kernel.org/stable/c/e68035178e65e2b3aa386ce61202ff33724ae418"},{"url":"https://git.kernel.org/stable/c/4837fb36219e6c08b666bc31a86841bad8526358"}],"tags":["cve.org"],"epss":0.00652,"epssPercentile":0.50216,"ingestedAt":"2026-10-16T19:46:24.392Z","slug":"CVE-2026-72472","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnfs: use nfsi->rwsem to protect traversal of the file lock list\n\nLingfeng identified a bug and suggested two solutions, but both appear\nto have issues.\n\nGenerally, we cannot release flc_lock while iterating over the file lock\nlist to avoid use-after-free (UAF) problems with file locks. However,\nfunctions like nfs_delegation_claim_locks and nfs4_reclaim_locks cannot\nadhere to this rule because recover_lock or nfs4_lock_delegation_recall\nmay take a long time. To resolve this, NFS switches to using nfsi->rwsem\nfor the same protection, and nfs_reclaim_locks follows this approach.\nAlthough nfs_delegation_claim_locks uses so_delegreturn_mutex instead,\nthis is inadequate since a single inode can have multiple nfs4_state\ninstances. Therefore, the fix is to also use nfsi->rwsem in this case.\n\nFurthermore, after commit c69899a17ca4 (\"NFSv4: Update of VFS byte range\nlock must be atomic with the stateid update\"), the functions\nnfs4_locku_done and nfs4_lock_done also break this rule because they\ncall locks_lock_inode_wait without holding nfsi->rwsem. Simply adding\nthis protection could cause many deadlocks, so instead, the call to\nlocks_lock_inode_wait is moved into _nfs4_proc_setlk. Regarding the bug\nfixed by commit c69899a17ca4 (\"NFSv4: Update of VFS byte range\nlock must be atomic with the stateid update\"), it has been resolved\nafter commit 0460253913e5 (\"NFSv4: nfs4_do_open() is incorrectly triggering\nstate recovery\") because all slots are drained before calling\nnfs4_do_reclaim, which prevents concurrent stateid changes along this path.\nAlso, nfs_delegation_claim_locks does not cause this concurrency either\nsince when _nfs4_proc_setlk is called with NFS_DELEGATED_STATE, no RPC is\nsent, so nfs4_lock_done is not called. Therefore,\nnfs4_lock_delegation_recall from nfs_delegation_claim_locks is the first\ntime the stateid is set.\n\n## Affected\n\n- `Linux >= c69899a17ca4836230720e65493942d9582a0424 < 1cda95bf2e9c0e6b63545b7565fe4a1e474322f4`\n- `Linux >= c69899a17ca4836230720e65493942d9582a0424 < f161ef7b0dd2f51fdb002ba4a4e9bf0ee7409218`\n- `Linux >= c69899a17ca4836230720e65493942d9582a0424 < e68035178e65e2b3aa386ce61202ff33724ae418`\n- `Linux >= c69899a17ca4836230720e65493942d9582a0424 < 4837fb36219e6c08b666bc31a86841bad8526358`\n- `Linux 4.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}