What’s Vulnerable › Vulnerabilities

CVE-2026-93829: smb: client: fix races in cifsd thread creation

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-24 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix races in cifsd thread creation The cifsd demultiplex thread can run and access tcp_ses before the parent thread has finished populating tcp_ses, which the worker thread accesses locklessly. Also, the kthread_run macro may start the thread before returning the thread pointer. Because the pointer is part of the structure that the thread can access, if the kernel is preempted after the thread is spawned, but before the thread pointer is populated and the thread attempts to exit, it will sleep, waiting for a SIGKILL signal. Fix this by moving creation of the thread to after all of tcp_ses'es fields are populated, and spawning the thread last, using a split kthread_create/wake_up_process logic.

Affected products

• Linux: 2.6.22 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux 7.2. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/0eee1e6cddd1d9ce14da06e0238ca8d3362dec90
• https://git.kernel.org/stable/c/2376fb3348b4fa72a5158c8a63ff2489e1956541
• https://git.kernel.org/stable/c/cfa09f63e75cf440c9be97d1e73d509bfbb2c2c5
• https://git.kernel.org/stable/c/e8a5cf2ff5a13fefb228f2069e29dd7d8e37185d
• https://git.kernel.org/stable/c/ee8f811cbac56ffb738b3a73671a9e75b0f56e99

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