ghsa-x82v-x9cm-j5mp
Vulnerability from github
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": [],
"aliases": [
"CVE-2025-40002"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-18T08:15:34Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: Fix use-after-free in tb_dp_dprx_work\n\nThe original code relies on cancel_delayed_work() in tb_dp_dprx_stop(),\nwhich does not ensure that the delayed work item tunnel-\u003edprx_work has\nfully completed if it was already running. This leads to use-after-free\nscenarios where tb_tunnel is deallocated by tb_tunnel_put(), while\ntunnel-\u003edprx_work remains active and attempts to dereference tb_tunnel\nin tb_dp_dprx_work().\n\nA typical race condition is illustrated below:\n\nCPU 0 | CPU 1\ntb_dp_tunnel_active() |\n tb_deactivate_and_free_tunnel()| tb_dp_dprx_start()\n tb_tunnel_deactivate() | queue_delayed_work()\n tb_dp_activate() |\n tb_dp_dprx_stop() | tb_dp_dprx_work() //delayed worker\n cancel_delayed_work() |\n tb_tunnel_put(tunnel); |\n | tunnel = container_of(...); //UAF\n | tunnel-\u003e //UAF\n\nReplacing cancel_delayed_work() with cancel_delayed_work_sync() is\nnot feasible as it would introduce a deadlock: both tb_dp_dprx_work()\nand the cleanup path acquire tb-\u003elock, and cancel_delayed_work_sync()\nwould wait indefinitely for the work item that cannot proceed.\n\nInstead, implement proper reference counting:\n- If cancel_delayed_work() returns true (work is pending), we release\n the reference in the stop function.\n- If it returns false (work is executing or already completed), the\n reference is released in delayed work function itself.\n\nThis ensures the tb_tunnel remains valid during work item execution\nwhile preventing memory leaks.\n\nThis bug was found by static analysis.",
"id": "GHSA-x82v-x9cm-j5mp",
"modified": "2025-10-18T09:30:51Z",
"published": "2025-10-18T09:30:51Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40002"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/67600ccfc4f38ebd331b9332ac94717bfbc87ea7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c07923f6a8729fc27ee652221a51702ff6654097"
}
],
"schema_version": "1.4.0",
"severity": []
}
Sightings
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