Improper control of a resource through its lifetime in Linux kernel - CVE-2026-63812
Published: July 21, 2026
Vulnerability identifier: #VU138836
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63812
CWE-ID: CWE-664
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper state management in __destroy_extent_node() and the f2fs extent cache when handling extent node destruction and concurrent writeback. A local user can trigger inode eviction or writeback activity to cause a kernel sanity check failure and filesystem inconsistency.
The issue can leave the cached largest extent stale after the FI_NO_EXTENT flag is set, and concurrency with writeback is involved in the affected path.
Affected software
Linux kernel
How to mitigate CVE-2026-63812
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
External References
- https://git.kernel.org/stable/c/1f70ddb28a3c71df124da5fa4040c808116d6bb9
- https://git.kernel.org/stable/c/20190e498057997532c7f186d081011f18e0a462
- https://git.kernel.org/stable/c/58a5deb220bcac4c73bf58954c0845644c997487
- https://git.kernel.org/stable/c/7e4d8f98be63f98856a5176b9188dada6e7ba9ee
- https://git.kernel.org/stable/c/edf12cbeeeabe799bd2ee21fdb5c336cce6fbad7