CVE-2026-89712 Linux Kernel - Use After Free

Linux kernel contains a use-after-free vulnerability in NFSD nfsd4_ssc_expire_umount caused by improper handling of list iteration after dropping nfsd_ssc_lock, letting attackers cause denial of service by crashing the kernel, exploit requires concurrent NFS RPC threads.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
None known
EPSS
0.71% 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 NFSD nfsd4_ssc_expire_umount.

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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