cbcvebase.
CVE-2025-40002
published 2025-10-18

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…

PriorityP424
EPSS
0.24%
14.6th percentile
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.

Affected

9 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.17.6-1 (forky)linux 6.17.6-1 (forky)
linuxlinux
linuxlinux>= d6d458d42e1e1544a18f37f1d5c840e00d5261b9 < c07923f6a8729fc27ee652221a51702ff6654097c07923f6a8729fc27ee652221a51702ff6654097
linuxlinux>= d6d458d42e1e1544a18f37f1d5c840e00d5261b9 < 67600ccfc4f38ebd331b9332ac94717bfbc87ea767600ccfc4f38ebd331b9332ac94717bfbc87ea7
linuxlinux_kernel>= 0 < 6.17.6-16.17.6-1
linuxlinux_kernel>= 0 < 6.17.0-14.146.17.0-14.14
linuxlinux_kernel>= 6.14.0 < 6.17.36.17.3
ubuntulinux-aws
ubuntulinux-oracle
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