CVE-2026-98261

cifs: Fix server use-after-free in cifs_chan_skip_or_disable()

State: Published
Severity: 8.1 High
Published: Oct 6, 2026
Updated: Oct 19, 2026
Reserved: Sep 25, 2026

Description

In the Linux kernel, the following vulnerability has been resolved:

cifs: Fix server use-after-free in cifs_chan_skip_or_disable()

When a secondary channel is no longer supported by the server, cifs_chan_skip_or_disable() drops the channel reference with cifs_put_tcp_session() and then continues to use the server pointer by calling cifs_signal_cifsd_for_reconnect() on it and reading its primary_server pointer. cifs_put_tcp_session() can drop the last reference of the channel and tear it down, so both the channel and the primary server (whose reference is also dropped by cifs_put_tcp_session()) can be freed before they are signaled for reconnect.

Signal the channel and the primary server and capture the primary server pointer before dropping the channel reference with cifs_put_tcp_session().

Scores

CVSS	Score	Vector	Source
3.1	8.1 High	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	50e8363ecc85da49764781da90ebffe1a657b370 to before 0338489960ddad6368bce55e8adbc176c523093dAffected f591062bdbf4742b7f1622173017f19e927057b0 to before edd52eae5fcfb8433b6bb0e7cd98db438fe01227Affected f591062bdbf4742b7f1622173017f19e927057b0 to before fcc0a935bb6e37ecbf7e4335061309f896f35780Affected f591062bdbf4742b7f1622173017f19e927057b0 to before 7a1b27780b113583a94256d58dabfe7c0d9286e7Affected f591062bdbf4742b7f1622173017f19e927057b0 to before 717e0a25036b6c92cecace30913b2d874a4c22b8Affected d61ba1d71ea6039eca7ada870bf3f0c3c8fc12e4Affected 6.6.15 to before 6.6.158Affected 6.7.3 to before 6.8Affected
LinuxLinux	6.8Affected before 6.8Not affected 6.6.158 through 6.6.Not affected 6.12.112 through 6.12.Not affected 6.18.54 through 6.18.Not affected 7.2.8 through 7.2.Not affected 7.3 and laterNot affected

Product

Versions

LinuxLinux

50e8363ecc85da49764781da90ebffe1a657b370 to before 0338489960ddad6368bce55e8adbc176c523093dAffected
f591062bdbf4742b7f1622173017f19e927057b0 to before edd52eae5fcfb8433b6bb0e7cd98db438fe01227Affected
f591062bdbf4742b7f1622173017f19e927057b0 to before fcc0a935bb6e37ecbf7e4335061309f896f35780Affected
f591062bdbf4742b7f1622173017f19e927057b0 to before 7a1b27780b113583a94256d58dabfe7c0d9286e7Affected
f591062bdbf4742b7f1622173017f19e927057b0 to before 717e0a25036b6c92cecace30913b2d874a4c22b8Affected
d61ba1d71ea6039eca7ada870bf3f0c3c8fc12e4Affected
6.6.15 to before 6.6.158Affected
6.7.3 to before 6.8Affected

LinuxLinux

6.8Affected
before 6.8Not affected
6.6.158 through 6.6.*Not affected
6.12.112 through 6.12.*Not affected
6.18.54 through 6.18.*Not affected
7.2.8 through 7.2.*Not affected
7.3 and laterNot affected

References

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