CVE-2026-63817: f2fs: validate compress cache inode only when enabled

highCVSS 7.1CVE-2026-63817

CSIRTS triage

vendor: Linux product: f2fsOther

What: The f2fs file system does not validate compress cache inode when it is enabled.
Who is affected: Deployments of the Linux kernel using f2fs.
Urgency: Remediation is necessary to prevent potential issues with file system integrity.
Action: Update to the latest kernel version.

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

⚡ Watch f2fs

Get an email when a new f2fs advisory drops — max one per day, one-click unsubscribe.

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: high — CVSS 7.1
Published: 2026-07-14
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-63817

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-2026-638170.13% 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-2026-63817	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 f2fs

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-2026-63820: In the Linux kernel, the following vulnerability has been resolved: f2fs: fix missing read bio…nvd · 2026-07-19
highCVE-2026-63819: In the Linux kernel, the following vulnerability has been resolved: f2fs: fix to do sanity che…nvd · 2026-07-19
highCVE-2026-63818: In the Linux kernel, the following vulnerability has been resolved: f2fs: validate orphan inod…nvd · 2026-07-19
highCVE-2026-63817: In the Linux kernel, the following vulnerability has been resolved: f2fs: validate compress ca…nvd · 2026-07-19
highCVE-2026-63816: In the Linux kernel, the following vulnerability has been resolved: f2fs: atomic: fix UAF issu…nvd · 2026-07-19
highCVE-2026-63815: In the Linux kernel, the following vulnerability has been resolved: f2fs: bound i_inline_xattr…nvd · 2026-07-19