Medium 5.5Published Jul 19, 2026

CVE-2026-53393nfsd: reset write verifier on deferred writeback errors

Updated under an hour ago (Oct 26, 2026, 5:10 PM ET)

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Exploited in the last 30 days

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: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Analyzed
Record last updated: Aug 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from f14816f2f928c560d28ba344af689f56efcd6f55 before b8e5894e56cff70fa245628fe16f0ad6367f8090; from 3145fe0ebb16e1715ad541a301bc6675c8375fcd before bc2baca02ec56da7707a74ed5d340b0a1dff1841; 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb builds before 43b65d2997963e80e8d8d86520bcb1e0751227de; from 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb before 666e837b247fcadf2d8d508b9b0e49d720393eb4; 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb builds before 1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e; from 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb before 4367afc119c51e17a616f6908772b7e2c2c4013f; from 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb before b027cca33c97354149fcc0ddeede4525c41093cd; from 555dbf1a9aac6d3150c8b52fa35f768a692f4eeb before 2090b05803faab8a9fa62fbff871007862cac1b7; and 2 more ranges	CNA record
linux linux_kernel linux:linux_kernel	from 5.10.124 before 5.10.261; from 5.15.49 before 5.15.212; from 5.17 before 6.1.178; from 6.2 before 6.6.145; from 6.7 before 6.12.95; from 6.13 before 6.18.38; from 6.19 before 7.1.3	NVD

References

References

https://git.kernel.org/stable/c/b8e5894e56cff70fa245628fe16f0ad6367f8090	patch
https://git.kernel.org/stable/c/bc2baca02ec56da7707a74ed5d340b0a1dff1841	patch
https://git.kernel.org/stable/c/43b65d2997963e80e8d8d86520bcb1e0751227de	patch
https://git.kernel.org/stable/c/666e837b247fcadf2d8d508b9b0e49d720393eb4	patch
https://git.kernel.org/stable/c/1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e	patch
https://git.kernel.org/stable/c/4367afc119c51e17a616f6908772b7e2c2c4013f	patch
https://git.kernel.org/stable/c/b027cca33c97354149fcc0ddeede4525c41093cd	patch
https://git.kernel.org/stable/c/2090b05803faab8a9fa62fbff871007862cac1b7	patch

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.