VulnerabilityPublished 19 Jul 2026

CVE-2026-63811: Linux kernel · f2fs: read COW data with the original inode during atomic write

Source GCVE Database

Authoritative record:CVE-2026-63811

Not known to be exploited · fixed in bcc9df992f3cbc43f2ecfe0b22e428e50f326e72 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.1% chance of exploitation in 30 days – higher than 2% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in bcc9df992f3cbc43f2ecfe0b22e428e50f326e72, a92332f32a8d31a7eee47b1dc1d751cb3319908f, a41075acde0124d2f8a5f563068a5d63e8ffd57b +2

Exploitation evidence

Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

ghsa-wqxg-ff3c-39jf

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 591fc34e1f98b0d7eef4aa3440bfdff3c5a1cadd, < bcc9df992f3cbc43f2ecfe0b22e428e50f326e72	Fixed in bcc9df992f3cbc43f2ecfe0b22e428e50f326e72
LinuxLinux	Affected ≥ 591fc34e1f98b0d7eef4aa3440bfdff3c5a1cadd, < a92332f32a8d31a7eee47b1dc1d751cb3319908f	Fixed in a92332f32a8d31a7eee47b1dc1d751cb3319908f
LinuxLinux	Affected ≥ 591fc34e1f98b0d7eef4aa3440bfdff3c5a1cadd, < a41075acde0124d2f8a5f563068a5d63e8ffd57b	Fixed in a41075acde0124d2f8a5f563068a5d63e8ffd57b
LinuxLinux	Affected ≥ 591fc34e1f98b0d7eef4aa3440bfdff3c5a1cadd, < 655d55c5740d37ffdf6233ff5fe21cea879407f1	Fixed in 655d55c5740d37ffdf6233ff5fe21cea879407f1
LinuxLinux	Affected ≥ 591fc34e1f98b0d7eef4aa3440bfdff3c5a1cadd, < 7e4ab3907f44dc243d026048d7f5d477dae9267b	Fixed in 7e4ab3907f44dc243d026048d7f5d477dae9267b
LinuxLinux	Affected =6.4	Fixed in–

AI-suggested

A fix for this vulnerability has been implemented in the Linux kernel by removing the use of the COW inode for decryption decisions during atomic writes in f2fs. Users should apply the official kernel updates that include this patch. Patch status is not explicitly confirmed in the provided data; therefore, check the Linux kernel vendor advisory or distribution security updates for the official fix.

Description

A vulnerability in the Linux kernel's f2fs filesystem was resolved involving atomic write operations. The issue caused f2fs_write_begin() to read data from a copy-on-write (COW) inode with a different encryption context than the original inode, leading to a null pointer dereference and kernel crash. The fix removes the use of the COW inode for decryption decisions, ensuring the original inode's encryption context is used correctly.

References

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