CVE-2026-89689 Linux Kernel nfsd - Use After Free

Linux kernel nfsd contains a use-after-free vulnerability caused by improper freeing of session slots in nfsd4_sequence(), letting attackers cause memory corruption and potential denial of service, exploit requires crafted NFSv4 client requests.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.65% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Use After Free
Impact
Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
11 September 2026
Updated
15 October 2026

Vendor fix

Update to the latest Linux kernel version containing the fix for session slot freeing in nfsd4_sequence.

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

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