UnratedFix available
nfsd: reset write verifier on deferred writeback errors
Type: advisorySources: OSV
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.
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.10.261, 5.15.212, 6.1.178, 6.12.95, 6.18.38, 6.6.145, 7.1.3
- CVEs
- CVE-2026-53393
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 20:01 UTC · Revision 1
Source evidence
nfsd: reset write verifier on deferred writeback errors
core-osv · Original sourcePublished 19 Jul 2026, 12:01 UTC
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.
osv:CVE-2026-53393
Kernel
Fixed versions: 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.95, 6.18.38, 7.1.3
Complete source record
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