CVE-2026-89639 Linux Kernel - Cache Invalidation Issue in CIFS Truncate

Linux kernel contains a cache invalidation issue in cifs_do_truncate() caused by improper cache handling without i_rwsem, letting attackers cause stale cached data to be served, exploit requires file truncation with O_TRUNC flag.

CVSS base score 7.1 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.17% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Cache Invalidation Issue in CIFS Truncate
Impact
Information Disclosure
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
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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