CVE-2026-63804: gfs2: fix use-after-free in gfs2_qd_dealloc

highCVSS 7.8CVE-2026-63804

CSIRTS triage

vendor: Linux product: gfs2Other

What: There is a use-after-free vulnerability in gfs2_qd_dealloc.
Who is affected: Deployments of gfs2 are affected.
Urgency: Remediation is necessary as use-after-free vulnerabilities can lead to exploitation.
Action: Apply the latest patches to fix the vulnerability.

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: 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-2026-63804

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-2026-638040.14% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 4% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-63804	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 gfs2

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-2026-63804: In the Linux kernel, the following vulnerability has been resolved: gfs2: fix use-after-free i…nvd · 2026-07-19
criticalCVE-2026-53049: gfs2: add some missing log lockingmsrc · 2026-06-09
mediumCVE-2026-53048: gfs2: prevent NULL pointer dereference during unmountmsrc · 2026-06-09