CVE-2026-64266: fuse: re-lock request before returning from fuse_ref_folio()

highCVSS 7.8CVE-2026-64266

CSIRTS triage

Other

What: A re-lock request is made before returning from the function fuse_ref_folio().
Who is affected: Deployments using the fuse subsystem.
Urgency: Remediation is necessary to prevent potential issues, though exploitation is not currently reported.
Action: Apply the relevant patches when available.

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

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.8
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-64266

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-2026-642660.16% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 6% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-64266	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 fuse

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-2026-52791: fuse-overlayfs is an implementation of overlayfs in FUSE for rootless containers. Prior to 1.1…nvd · 2026-07-29
unknownCVE-2026-64267: In the Linux kernel, the following vulnerability has been resolved: fuse: avoid 32-bit prune n…nvd · 2026-07-25
highCVE-2026-64266: In the Linux kernel, the following vulnerability has been resolved: fuse: re-lock request befo…nvd · 2026-07-25
highCVE-2026-64265: In the Linux kernel, the following vulnerability has been resolved: fuse: clear intr_entry in …nvd · 2026-07-25
unknownCVE-2026-64264: In the Linux kernel, the following vulnerability has been resolved: fuse-uring: fix EFAULT clo…nvd · 2026-07-25
unknownCVE-2026-64263: In the Linux kernel, the following vulnerability has been resolved: fuse-uring: fix moving can…nvd · 2026-07-25