CVE-2026-53393: nfsd: reset write verifier on deferred writeback errors

mediumCVSS 5.9CVE-2026-53393

CSIRTS triage

vendor: Linux product: nfsdOther

What: This vulnerability resets the write verifier on deferred writeback errors.
Who is affected: Deployments using the nfsd service.
Urgency: Remediation is important to maintain data integrity, with no current exploitation reported.
Action: Reset the write verifier on deferred writeback errors.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 5.9
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-53393

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-533930.13% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 3% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-53393	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for nfsd

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2026-64519: In the Linux kernel, the following vulnerability has been resolved: NFSD: Fix infinite loop in…nvd · 2026-07-25
criticalCVE-2026-53399: In the Linux kernel, the following vulnerability has been resolved: nfsd: release layout stid …nvd · 2026-07-19
criticalCVE-2026-53398: In the Linux kernel, the following vulnerability has been resolved: NFSD: Fix SECINFO_NO_NAME …nvd · 2026-07-19
highCVE-2026-53397: In the Linux kernel, the following vulnerability has been resolved: nfsd: fix posix_acl leak o…nvd · 2026-07-19
highCVE-2026-53396: In the Linux kernel, the following vulnerability has been resolved: nfsd: fix posix_acl leak a…nvd · 2026-07-19
highCVE-2026-53395: In the Linux kernel, the following vulnerability has been resolved: nfsd: fix dead ACL conflic…nvd · 2026-07-19