Improper update of reference count in Linux kernel - CVE-2026-89841
Published: September 17, 2026
Vulnerability identifier: #VU150453
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89841
CWE-ID: CWE-911
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 reference count handling in the f2fs redirty_blocks() function when a folio fails to be pinned. A local user can trigger block redirtying to cause a denial of service.
The issue requires the failed folio to have already been populated in the page cache by readahead.
Affected software
Linux kernel
How to mitigate CVE-2026-89841
Install security update from vendor's repository.