CVE-2026-53393
In the Linux kernel, the following vulnerability has been resolved: nfsd: reset write verifier on deferred writeback errors nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to detect deferred writeback errors, but neither rotates the…
Does this matter?
Lower severity and a low EPSS score (0.13%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: nfsd: reset write verifier on deferred writeback errors nfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to detect deferred writeback errors, but neither rotates the server's write verifier (nn->writeverf) when this check fails. Every other durable-storage-failure path in these functions calls commit_reset_write_verifier() before returning an error. The missing rotation means clients holding UNSTABLE write data under the current verifier will COMMIT, receive the unchanged verifier back, and conclude their data is durable — silently dropping data that failed writeback. This violates the UNSTABLE+COMMIT durability contract (RFC 1813 §3.3.7, RFC 8881 §18.32). Add commit_reset_write_verifier() calls at both filemap_check_wb_err() error sites, matching the pattern used by adjacent error paths in the same functions. The helper already filters -EAGAIN and -ESTALE internally, so the calls are unconditionally safe.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.13% probability · 3th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/1dd664b39774a9c89b72de8e59bf9ef4b3aaff2ePatch
- https://git.kernel.org/stable/c/2090b05803faab8a9fa62fbff871007862cac1b7Patch
- https://git.kernel.org/stable/c/4367afc119c51e17a616f6908772b7e2c2c4013fPatch
- https://git.kernel.org/stable/c/43b65d2997963e80e8d8d86520bcb1e0751227dePatch
- https://git.kernel.org/stable/c/666e837b247fcadf2d8d508b9b0e49d720393eb4Patch
- https://git.kernel.org/stable/c/b027cca33c97354149fcc0ddeede4525c41093cdPatch
- https://git.kernel.org/stable/c/b8e5894e56cff70fa245628fe16f0ad6367f8090Patch
- https://git.kernel.org/stable/c/bc2baca02ec56da7707a74ed5d340b0a1dff1841Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.