CVE-2026-98261

Received Received - Intake

BaseFortify

Publication date: 2026-10-06

Last updated on: 2026-10-19

Assigner: kernel.org

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().

CVSS Scores

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Meta Information

Published

2026-10-06

Last Modified

2026-10-19

Generated

2026-10-19

AI Q&A

2026-10-06

EPSS Evaluated

2026-10-18

NVD

CVE-2026-98261

EUVD

EUVD-2026-93189

Affected Vendors & Products

Vendor	Product	Version / Range
Linux	Linux	50e8363ecc85da49764781da90ebffe1a657b370
Linux	Linux	f591062bdbf4742b7f1622173017f19e927057b0
Linux	Linux	f591062bdbf4742b7f1622173017f19e927057b0
Linux	Linux	f591062bdbf4742b7f1622173017f19e927057b0
Linux	Linux	f591062bdbf4742b7f1622173017f19e927057b0
Linux	Linux	d61ba1d71ea6039eca7ada870bf3f0c3c8fc12e4
Linux	Linux	6.6.15
Linux	Linux	6.7.3
Linux	Linux	6.8

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This is a use-after-free vulnerability in the Linux kernel's CIFS (Common Internet File System) component. It occurs when a secondary channel is no longer supported by the server. The function cifs_chan_skip_or_disable() incorrectly drops a channel reference and then continues using the server pointer after it may have been freed, leading to potential memory corruption or crashes.

Detection Guidance

This vulnerability is specific to the Linux kernel's CIFS (Common Internet File System) implementation. Detection requires checking the kernel version and CIFS module behavior. Use 'uname -r' to check the kernel version and 'lsmod | grep cifs' to verify if the CIFS module is loaded. If the kernel version is vulnerable, monitor logs for CIFS-related errors or crashes.

Impact Analysis

This vulnerability could cause system instability, crashes, or unexpected behavior in systems using the CIFS protocol for file sharing. Attackers might exploit it to trigger denial-of-service conditions or execute arbitrary code with kernel privileges, depending on the system configuration.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it pertains to a use-after-free issue in the Linux kernel's CIFS (Common Internet File System) module. Compliance impacts would depend on how the affected system is used, but the vulnerability itself is not a compliance violation.

Mitigation Strategies

Immediately update the Linux kernel to a patched version that includes the fix for CVE-2026-98261. If updating is not immediately possible, disable the CIFS module using 'sudo rmmod cifs' or block CIFS traffic at the network level until the patch is applied.

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