CVE Catalog

CVE-2026-53393

MediumCVSS 5.5
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.13%

3th percentile - higher than 3% of all known CVEs

Summary

In the Linux kernel's NFS server (nfsd), the write verifier is not rotated after detecting a deferred writeback error. This causes the NFS client to receive an unchanged verifier and incorrectly assume data is durable, leading to silent data loss.

Risk Assessment

The organization risks silent data loss during NFS COMMIT operations, violating the UNSTABLE+COMMIT durability contract and potentially causing irreversible data corruption.

Recommendation

Apply the Linux kernel patch that adds commit_reset_write_verifier() calls at the writeback error detection points in nfsd_vfs_write() and nfsd_commit().

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS