CVE-2026-89688 Linux Kernel - Use After Free

Linux kernel contains a use-after-free vulnerability caused by incorrect reference counting in nfsd4_cstate_assign_replay() during seqid_op replay retry, letting attackers cause memory corruption or denial of service, exploit requires attacker to trigger specific NFSv4 operations.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.74% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Use After Free
Impact
Use After Free, 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 nfsd stateid reference handling.

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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