CVE-2026-89637 Linux kernel smb client - Use After Free

Linux kernel smb client contains a use-after-free and buffer leak caused by improper handling of malformed secondary TRANSACT2 responses in cifs_check_trans2(), letting attackers cause memory corruption, exploit requires crafted malformed secondary T2 response.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.58% 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.

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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