Incorrect calculation in Linux kernel - CVE-2026-89678
Published: September 12, 2026
Vulnerability identifier: #VU149128
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-89678
CWE-ID: CWE-682
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to corrupt file data and cause incorrect write-count reporting.
The vulnerability exists due to incorrect partial-write detection in nfsd_direct_write() when processing direct-write segments that complete partially. A remote attacker can submit a write request that results in a partial segment write to corrupt file data and cause incorrect write-count reporting.
Only short writes completing between 50% and 99% of a segment bypass detection.
Affected software
Linux kernel
How to mitigate CVE-2026-89678
Install security update from vendor's repository.