CVE-2026-89713 Linux Kernel NFSD - Race Condition

Linux kernel NFSD contains a time-of-check to time-of-use (TOCTOU) vulnerability caused by checking truncate permission without inode lock, letting attackers bypass append-only file restrictions during concurrent file size changes, exploit requires concurrent file append operations.

CVSS base score 9.1 /10
Critical
CISA KEV
Not listed
Public exploit
None known
EPSS
0.61% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Race Condition
Impact
Data Tampering
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
Published
11 September 2026
Updated
15 October 2026

Vendor fix

Update to the latest Linux kernel version with the NFSD inode lock fix.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

← All CVEs