{"id":"CVE-2025-40002","state":"PUBLISHED","title":"thunderbolt: Fix use-after-free in tb_dp_dprx_work","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.","publishedAt":"2025-10-18T08:03:22.718Z","updatedAt":"2026-05-11T21:40:34.575Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d6d458d42e1e1544a18f37f1d5c840e00d5261b9","status":"affected","lessThan":"c07923f6a8729fc27ee652221a51702ff6654097","versionType":"git"},{"version":"d6d458d42e1e1544a18f37f1d5c840e00d5261b9","status":"affected","lessThan":"67600ccfc4f38ebd331b9332ac94717bfbc87ea7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/thunderbolt/tunnel.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.14","versionType":"semver"},{"version":"6.17.3","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/thunderbolt/tunnel.c"]}],"references":["https://git.kernel.org/stable/c/c07923f6a8729fc27ee652221a51702ff6654097","https://git.kernel.org/stable/c/67600ccfc4f38ebd331b9332ac94717bfbc87ea7"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:09.358Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/40xxx/CVE-2025-40002.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-40002","state":"PUBLISHED","datePublished":"2025-10-18T08:03:22.718Z","dateUpdated":"2026-05-11T21:40:34.575Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T07:20:57.151Z"},"containers":{"cna":{"title":"thunderbolt: Fix use-after-free in tb_dp_dprx_work","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d6d458d42e1e1544a18f37f1d5c840e00d5261b9","status":"affected","lessThan":"c07923f6a8729fc27ee652221a51702ff6654097","versionType":"git"},{"version":"d6d458d42e1e1544a18f37f1d5c840e00d5261b9","status":"affected","lessThan":"67600ccfc4f38ebd331b9332ac94717bfbc87ea7","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/thunderbolt/tunnel.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.14","versionType":"semver"},{"version":"6.17.3","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/thunderbolt/tunnel.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c07923f6a8729fc27ee652221a51702ff6654097"},{"url":"https://git.kernel.org/stable/c/67600ccfc4f38ebd331b9332ac94717bfbc87ea7"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:40:34.575Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"6.17.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.14","versionEndExcluding":"6.18"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}