{"schema":"threatline.record/2","record":{"id":"CVE-2026-98694","aliases":[],"summary":"thunderbolt: Fix KASAN reported use-after-free when request is canceled","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nthunderbolt: Fix KASAN reported use-after-free when request is canceled\n\nAlan reported that when doing stress testing sometimes KASAN notices\nuse-after-free during control channel operation (stripped down keeping\nthe relevant parts):\n\n BUG: KASAN: slab-use-after-free in tb_cfg_request_sync+0x240/0x250 [thunderbolt]\n Read of size 24 at addr ffff88811067f290 by task kworker/u40:2/1760\n  <TASK>\n  tb_cfg_request_sync+0x240/0x250 [thunderbolt]\n  tb_cfg_read_raw+0x367/0x510 [thunderbolt]\n  tb_cfg_read+0xec/0x240 [thunderbolt]\n  tb_port_get_link_generation+0x258/0x420 [thunderbolt]\n  tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]\n  tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]\n  tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]\n  tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]\n  tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]\n  process_one_work+0x675/0x1230\n  worker_thread+0x5e6/0xf70\n  kthread+0x365/0x470\n  ret_from_fork+0x54d/0x710\n  ret_from_fork_asm+0x1a/0x30\n  </TASK>\n\n Allocated by task 1760:\n  __kmalloc_cache_noprof+0x1ee/0x550\n  tb_cfg_read_raw+0x1d3/0x510 [thunderbolt]\n  tb_cfg_read+0xec/0x240 [thunderbolt]\n  tb_port_get_link_generation+0x258/0x420 [thunderbolt]\n  tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]\n  tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]\n  tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]\n  tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]\n  tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]\n  process_one_work+0x675/0x1230\n  worker_thread+0x5e6/0xf70\n  kthread+0x365/0x470\n  ret_from_fork+0x54d/0x710\n  ret_from_fork_asm+0x1a/0x30\n\n Freed by task 926:\n  kfree+0x18f/0x4a0\n  tb_cfg_request_put+0xb7/0xe0 [thunderbolt]\n  tb_cfg_request_work+0x82/0x120 [thunderbolt]\n  process_one_work+0x675/0x1230\n  worker_thread+0x5e6/0xf70\n  kthread+0x365/0x470\n  ret_from_fork+0x54d/0x710\n  ret_from_fork_asm+0x1a/0x30\n\n Second to last potentially related work creation:\n  __queue_work+0x575/0xd00\n  queue_work_on+0x77/0x80\n  tb_cfg_request_cancel+0xc7/0x260 [thunderbolt]\n  tb_cfg_request_sync+0x1f6/0x250 [thunderbolt]\n  tb_cfg_read_raw+0x367/0x510 [thunderbolt]\n  tb_cfg_read+0xec/0x240 [thunderbolt]\n  tb_port_get_link_generation+0x258/0x420 [thunderbolt]\n  tb_usb3_consumed_bandwidth+0x1c1/0x2c0 [thunderbolt]\n  tb_tunnel_consumed_bandwidth+0xfd/0x910 [thunderbolt]\n  tb_available_bandwidth+0x5f2/0xeb0 [thunderbolt]\n  tb_recalc_estimated_bandwidth+0x2a0/0x1bc0 [thunderbolt]\n  tb_handle_dp_bandwidth_request+0x1897/0x5e20 [thunderbolt]\n  process_one_work+0x675/0x1230\n  worker_thread+0x5e6/0xf70\n  kthread+0x365/0x470\n  ret_from_fork+0x54d/0x710\n  ret_from_fork_asm+0x1a/0x30\n\nThe last stack trace is helpful because it shows that we are cancelling\na request and looking at tb_cfg_request_cancel() what might happen is\nthat tb_cfg_request_work() completes right before tb_cfg_request_cancel()\nstarts and because of this it will call schedule_work() queueing the\nsame work to run again. However, it is already removed from the\nrequest_queue and reference count is dropped so when\ntb_cfg_request_work() triggers again it will access memory that is\nalready released.\n\nFix this so that we first make sure a cancelled request is not handed\naway from tb_cfg_request_find() or scheduled to run. Then instead of\nrelying on the worker to clean up the request we will do it in\ntb_cfg_request_cancel() after the work is canceled from running. Make\ntb_cfg_request_dequeue() release the request only if it was actually\nremoved from the queue.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98694","source_modified_at":"2026-10-21T12:55:43.497Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1","lessThan":"b70b9c41f240c42bf6e728034537c0fe60c16ef4","status":"affected","versionType":"git"},{"version":"d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1","lessThan":"71b3c517e02af2c46ad58d4b3706b7c3cb24936d","status":"affected","versionType":"git"},{"version":"d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1","lessThan":"f18faa3d3b810d60a3005ae1b1d1866faa67d343","status":"affected","versionType":"git"},{"version":"d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1","lessThan":"08287212b622039212c972806f896f078dfd28e2","status":"affected","versionType":"git"},{"version":"d7f781bfdbf4eb7c5706c9974b8bf6d3c82e69c1","lessThan":"a02188ddc24b7872f0c5e0c5873f827318717803","status":"affected","versionType":"git"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98694","source_modified_at":"2026-10-21T12:55:43.497Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"Linux","vendor":"Linux","versions":[{"version":"4.13","status":"affected"},{"version":"0","lessThan":"4.13","status":"unaffected","versionType":"semver"},{"version":"6.6.160","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.113","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.56","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.2.10","lessThanOrEqual":"7.2.*","status":"unaffected","versionType":"semver"},{"version":"7.3","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98694","source_modified_at":"2026-10-21T12:55:43.497Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"71b3c517e02af2c46ad58d4b3706b7c3cb24936d","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98694","source_modified_at":"2026-10-21T12:55:43.497Z","fetched_at":"2026-10-23T18:45:31.882637Z","package":{"name":"Linux","ecosystem":null},"version":"08287212b622039212c972806f896f078dfd28e2","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":0.00168,"percentile":0.05723,"score_date":"2026-10-23"},"published_at":"2026-10-18T15:46:18.654Z","modified_at":"2026-10-21T12:55:43.497Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98694","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-21T12:55:43.497Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98694","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","EPSS"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/b70b9c41f240c42bf6e728034537c0fe60c16ef4"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/71b3c517e02af2c46ad58d4b3706b7c3cb24936d"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/f18faa3d3b810d60a3005ae1b1d1866faa67d343"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/08287212b622039212c972806f896f078dfd28e2"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/a02188ddc24b7872f0c5e0c5873f827318717803"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-21T12:55:43.497Z","content_hash":"55410b71f0504f5f9bef293cbdaa585cc32f44632682c2e74dbca9966af55ed3"}}