CVE-2025-40231

What it is

In the Linux kernel, the following vulnerability has been resolved: vsock: fix lock inversion in vsock_assign_transport() Syzbot reported a potential lock inversion deadlock between vsock_register_mutex and sk_lock-AF_VSOCK when vsock_linger() is called. The issue was introduced by commit 687aa0c5581b ("vsock: Fix transport_* TOCTOU") which added vsock_register_mutex locking in vsock_assign_transport() around the transport->release() call, that can call vsock_linger(). vsock_assign_transport() can be called with sk_lock held. vsock_linger() calls sk_wait_event() that temporarily releases and re-acquires sk_lock. During this window, if another thread hold vsock_register_mutex while trying to acquire sk_lock, a circular dependency is created. Fix this by releasing vsock_register_mutex before calling transport->release() and vsock_deassign_transport(). This is safe because we don't need to hold vsock_register_mutex while releasing the old transport, and we ensure the new transport won't disappear by obtaining a module reference first via try_module_get().

At a glance

Exploit odds

0.2% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2025-12-04 16:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-19 21:10 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.2% in the next 30 days (EPSS).
• Severity: not scored yet.
• Fix: none linked yet, which raises it.

Details

Published

2025-12-04 16:16 UTC

Last modified

2026-10-19 21:10 UTC

Exploit probability

0.2% · EPSS, next 30 days

Record status

Deferred

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2025-40231.md and follow it. Check whether this project is affected by CVE-2025-40231. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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