{"cve":"CVE-2025-40002","nvd":{"published":"2025-10-18T08:15:34.243","modified":"2026-10-19T21:10:00.160","status":"Deferred","description":"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->dprx_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->dprx_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-> //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->lock, 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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/67600ccfc4f38ebd331b9332ac94717bfbc87ea7","https://git.kernel.org/stable/c/c07923f6a8729fc27ee652221a51702ff6654097"],"products":[],"source":"nvd","synced_at":"2026-10-21T03:43:09.190223697+00:00"},"epss":{"cve":"CVE-2025-40002","score":0.00253,"percentile":0.1658,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}