CVE-2026-43215
Analyzed Analyzed - Analysis Complete
Race Condition in Linux Kernel CIFS Module

Publication date: 2026-05-06

Last updated on: 2026-05-11

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: cifs: Fix locking usage for tcon fields We used to use the cifs_tcp_ses_lock to protect a lot of objects that are not just the server, ses or tcon lists. We later introduced srv_lock, ses_lock and tc_lock to protect fields within the corresponding structs. This was done to provide a more granular protection and avoid unnecessary serialization. There were still a couple of uses of cifs_tcp_ses_lock to provide tcon fields. In this patch, I've replaced them with tc_lock.
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Meta Information
Published
2026-05-06
Last Modified
2026-05-11
Generated
2026-06-16
AI Q&A
2026-05-06
EPSS Evaluated
2026-06-15
NVD
CVE-2026-43215
EUVD
EUVD-2026-27777
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 6.7 (inc) to 6.12.75 (exc)
linux linux_kernel From 6.13 (inc) to 6.18.16 (exc)
linux linux_kernel From 6.19 (inc) to 6.19.6 (exc)
linux linux_kernel From 6.0 (inc) to 6.6.128 (exc)
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-667 The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
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Executive Summary

This vulnerability in the Linux kernel relates to improper locking usage in the CIFS (Common Internet File System) component, specifically for tcon (tree connection) fields.

Originally, a single lock called cifs_tcp_ses_lock was used to protect multiple objects, including server, session (ses), and tree connection (tcon) lists. Later, more granular locks (srv_lock, ses_lock, and tc_lock) were introduced to protect specific fields within their respective structures to avoid unnecessary serialization.

However, some uses of the old cifs_tcp_ses_lock remained for protecting tcon fields, which was incorrect. The vulnerability was fixed by replacing these remaining uses with the appropriate tc_lock, ensuring proper and granular locking.

Impact Analysis

Improper locking in kernel components like CIFS can lead to race conditions, data corruption, or system instability.

Because the vulnerability involved incorrect locking for tcon fields, it could potentially cause concurrency issues affecting file system operations over CIFS, possibly leading to crashes or data integrity problems.

Fixing the locking ensures more reliable and stable operation of CIFS in the Linux kernel.

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