{"id":"CVE-2026-53393","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: reset write verifier on deferred writeback errors\n\nnfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to\ndetect deferred writeback errors, but ne…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: reset write verifier on deferred writeback errors\n\nnfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to\ndetect 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":0.02968,"slug":"CVE-2026-53393","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: reset write verifier on deferred writeback errors\n\nnfsd_vfs_write() and nfsd_commit() both call filemap_check_wb_err() to\ndetect deferred writeback errors, but neither rotates the server's write\nverifier (nn->writeverf) when this check fails. Every other\ndurable-storage-failure path in these functions calls\ncommit_reset_write_verifier() before returning an error.\n\nThe missing rotation means clients holding UNSTABLE write data under the\ncurrent verifier will COMMIT, receive the unchanged verifier back, and\nconclude their data is durable — silently dropping data that failed\nwriteback. This violates the UNSTABLE+COMMIT durability contract\n(RFC 1813 §3.3.7, RFC 8881 §18.32).\n\nAdd commit_reset_write_verifier() calls at both filemap_check_wb_err()\nerror sites, matching the pattern used by adjacent error paths in the\nsame functions. The helper already filters -EAGAIN and -ESTALE\ninternally, so the calls are unconditionally safe.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}