CVE-2025-40002

CVE-2025-40002 is a security vulnerability that is still awaiting full analysis and scoring. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Description

In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Fix use-after-free in tb_dp_dprx_work The original code relies on cancel_delayed_work() in tb_dp_dprx_stop(), which does not ensure that the delayed work item tunnel->dprx_work has fully completed if it was already running. This leads to use-after-free scenarios where tb_tunnel is deallocated by tb_tunnel_put(), while tunnel->dprx_work remains active and attempts to dereference tb_tunnel in tb_dp_dprx_work(). A typical race condition is illustrated below: CPU 0 | CPU 1 tb_dp_tunnel_active() | tb_deactivate_and_free_tunnel()| tb_dp_dprx_start() tb_tunnel_deactivate() | queue_delayed_work() tb_dp_activate() | tb_dp_dprx_stop() | tb_dp_dprx_work() //delayed worker cancel_delayed_work() | tb_tunnel_put(tunnel); | | tunnel = container_of(...); //UAF | tunnel-> //UAF Replacing cancel_delayed_work() with cancel_delayed_work_sync() is not feasible as it would introduce a deadlock: both tb_dp_dprx_work() and the cleanup path acquire tb->lock, and cancel_delayed_work_sync() would wait indefinitely for the work item that cannot proceed. Instead, implement proper reference counting: - If cancel_delayed_work() returns true (work is pending), we release the reference in the stop function. - If it returns false (work is executing or already completed), the reference is released in delayed work function itself. This ensures the tb_tunnel remains valid during work item execution while preventing memory leaks. This bug was found by static analysis.

Frequently asked questions

What is CVE-2025-40002?
In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Fix use-after-free in tb_dp_dprx_work The original code relies on cancel_delayed_work() in tb_dp_dprx_stop(), which does not ensure that the delayed work item tunnel->dprx_work has fully completed if it was already running. This leads to use-after-free scenarios where tb_tunnel is deallocated by tb_tunnel_put(), while tunnel->dprx_work remains active and attempts to dereference tb_tunnel in tb_dp_dprx_work(). A typical race condition is illustrated below: CPU 0 | CPU 1 tb_dp_tunnel_active() | tb_deactivate_and_free_tunnel()| tb_dp_dprx_start() tb_tunnel_deactivate() | queue_delayed_work() tb_dp_activate() | tb_dp_dprx_stop() | tb_dp_dprx_work() //delayed worker cancel_delayed_work() | tb_tunnel_put(tunnel); | | tunnel = container_of(...); //UAF | tunnel-> //UAF Replacing cancel_delayed_work() with cancel_delayed_work_sync() is not feasible as it would introduce a deadlock: both tb_dp_dprx_work() and the cleanup path acquire tb->lock, and cancel_delayed_work_sync() would wait indefinitely for the work item that cannot proceed. Instead, implement proper reference counting: - If cancel_delayed_work() returns true (work is pending), we release the reference in the stop function. - If it returns false (work is executing or already completed), the reference is released in delayed work function itself. This ensures the tb_tunnel remains valid during work item execution while preventing memory leaks. This bug was found by static analysis.
Is CVE-2025-40002 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (14th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-40002?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-40002 have an EU (EUVD) identifier?
Yes. CVE-2025-40002 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-34987.
When was CVE-2025-40002 published?
CVE-2025-40002 was published on 2025-10-18 and last updated on 2026-06-17.

References