In the Linux kernel, the following vulnerability has been resolved:
nfsd: reset write verifier on deferred writeback errors
nfsdvfswrite() and nfsdcommit() both call filemapcheckwberr() 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 commitresetwrite_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 commitresetwriteverifier() calls at both filemapcheckwberr() 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_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53393.json",
"cna_assigner": "Linux"
}