---
id: CVE-2026-53393
title: |-
  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 ne…
summary: |-
  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 ne…
severity: none
published: '2026-07-19'
updated: '2026-07-19'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-53393'
references:
  - url: 'https://git.kernel.org/stable/c/1dd664b39774a9c89b72de8e59bf9ef4b3aaff2e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2090b05803faab8a9fa62fbff871007862cac1b7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4367afc119c51e17a616f6908772b7e2c2c4013f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b027cca33c97354149fcc0ddeede4525c41093cd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
ingestedAt: '2026-07-19T21:33:34.703Z'
epss: 0.00129
epssPercentile: 0.02961
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.