{"id":"CVE-2026-98736","state":"PUBLISHED","title":"Bluetooth: hci_conn: Lock parent access during enhanced SCO setup","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_conn: Lock parent access during enhanced SCO setup\n\nBluetooth: hci_conn: Lock parent access during enhanced SCO setup\n\nhci_enhanced_setup_sync() runs on the request workqueue without the\nhci_dev_lock held by its caller when setup was queued. Its CVSD\ncapability check and find_next_esco_param() dereference conn->parent\nwhile the receive workqueue can unlink and release that parent.\n\nThe following interleaving can cause a use-after-free:\n\n  hci_enhanced_setup_sync()       hci_disconn_complete_evt()\n  load conn->parent\n                                 hci_dev_lock()\n                                 hci_conn_del(ACL parent)\n                                   unlink SCO child\n                                   drop link's parent reference\n                                   clear child->parent\n                                   release ACL parent\n                                     bt_link_release()\n                                       kfree(parent)\n                                 hci_dev_unlock()\n  read parent->features[0][3]\n\nThe reference held for the queued SCO child does not keep its ACL parent\nalive after unlinking. Commit 42de40abe25d (\"Bluetooth: hci_conn: fix the\nSCO setup context lifetime\") protects the child stored in the queued\ncontext, but leaves these parent accesses unprotected.\n\nWith a 40 ms diagnostic delay after loading conn->parent, an instrumented\nkernel based on fd179f8a05be, which already contains 42de40abe25d,\n\n  BUG: KASAN: slab-use-after-free in hci_enhanced_setup_sync+0xda5/0xdf0\n  Read of size 1 at addr ffff888102204047 by task kworker/u17:0/93\n  Call Trace:\n   hci_enhanced_setup_sync+0xda5/0xdf0\n   hci_cmd_sync_work+0x13c/0x290\n   process_one_work+0x6b4/0x10e0\n\n  Allocated by task 92:\n   __hci_conn_add+0x304/0x1df0\n   hci_connect_acl+0x349/0x3e0\n   hci_connect_sco+0x3b/0x9a0\n   sco_sock_connect+0x475/0xca0\n\n  Freed by task 94:\n   kfree+0x121/0x3c0\n   bt_link_release+0x79/0xa0\n   device_release+0xc8/0x240\n   kobject_put+0x14d/0x280\n   hci_conn_del+0x524/0xe30\n   hci_disconn_complete_evt+0x403/0x8c0\n   hci_event_packet+0x71b/0xb20\n   hci_rx_work+0x293/0x730\n\nThe accessed address is 71 bytes into the freed ACL parent, at its\nfeatures[0][3] byte; the queued SCO child is a different object. The\ndiagnostic preserves the loaded parent across the delay, matching the\nunmodified compiled capability check, and does not change the parent\nreferences or teardown path.\n\nHold hci_dev_lock() across the codec switch, including every call to\nfind_next_esco_param(), and release it on all selection errors. Keep\nconfigure_datapath_sync() outside the critical section because it waits\nfor HCI events. Preserve parameter selection and existing return values.","publishedAt":"2026-10-18T15:47:14.076Z","updatedAt":"2026-10-30T12:39:13.042Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"48bf3b94c7331e11eaa6c89adc054a7bc7c0382e","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"70b55855eecb428d446344d827bda8725ce8b312","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"1239ef0fa809b5952fca679db3faa3e1c00e1dac","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"cabd58d9bb66d49d481f762ce986173db397435d","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"93a737e4e042f59673cd580d35214f278d7b757d","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"024e05f73a4c1263d031614bc36700ec135eecb4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/hci_conn.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/hci_conn.c"]}],"references":["https://git.kernel.org/stable/c/48bf3b94c7331e11eaa6c89adc054a7bc7c0382e","https://git.kernel.org/stable/c/70b55855eecb428d446344d827bda8725ce8b312","https://git.kernel.org/stable/c/1239ef0fa809b5952fca679db3faa3e1c00e1dac","https://git.kernel.org/stable/c/cabd58d9bb66d49d481f762ce986173db397435d","https://git.kernel.org/stable/c/93a737e4e042f59673cd580d35214f278d7b757d","https://git.kernel.org/stable/c/024e05f73a4c1263d031614bc36700ec135eecb4"],"weaknesses":[],"ingestedAt":"2026-10-30T12:58:04.520Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98736.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98736","state":"PUBLISHED","datePublished":"2026-10-18T15:47:14.076Z","dateUpdated":"2026-10-30T12:39:13.042Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.367Z"},"containers":{"cna":{"title":"Bluetooth: hci_conn: Lock parent access during enhanced SCO setup","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_conn: Lock parent access during enhanced SCO setup\n\nBluetooth: hci_conn: Lock parent access during enhanced SCO setup\n\nhci_enhanced_setup_sync() runs on the request workqueue without the\nhci_dev_lock held by its caller when setup was queued. Its CVSD\ncapability check and find_next_esco_param() dereference conn->parent\nwhile the receive workqueue can unlink and release that parent.\n\nThe following interleaving can cause a use-after-free:\n\n  hci_enhanced_setup_sync()       hci_disconn_complete_evt()\n  load conn->parent\n                                 hci_dev_lock()\n                                 hci_conn_del(ACL parent)\n                                   unlink SCO child\n                                   drop link's parent reference\n                                   clear child->parent\n                                   release ACL parent\n                                     bt_link_release()\n                                       kfree(parent)\n                                 hci_dev_unlock()\n  read parent->features[0][3]\n\nThe reference held for the queued SCO child does not keep its ACL parent\nalive after unlinking. Commit 42de40abe25d (\"Bluetooth: hci_conn: fix the\nSCO setup context lifetime\") protects the child stored in the queued\ncontext, but leaves these parent accesses unprotected.\n\nWith a 40 ms diagnostic delay after loading conn->parent, an instrumented\nkernel based on fd179f8a05be, which already contains 42de40abe25d,\n\n  BUG: KASAN: slab-use-after-free in hci_enhanced_setup_sync+0xda5/0xdf0\n  Read of size 1 at addr ffff888102204047 by task kworker/u17:0/93\n  Call Trace:\n   hci_enhanced_setup_sync+0xda5/0xdf0\n   hci_cmd_sync_work+0x13c/0x290\n   process_one_work+0x6b4/0x10e0\n\n  Allocated by task 92:\n   __hci_conn_add+0x304/0x1df0\n   hci_connect_acl+0x349/0x3e0\n   hci_connect_sco+0x3b/0x9a0\n   sco_sock_connect+0x475/0xca0\n\n  Freed by task 94:\n   kfree+0x121/0x3c0\n   bt_link_release+0x79/0xa0\n   device_release+0xc8/0x240\n   kobject_put+0x14d/0x280\n   hci_conn_del+0x524/0xe30\n   hci_disconn_complete_evt+0x403/0x8c0\n   hci_event_packet+0x71b/0xb20\n   hci_rx_work+0x293/0x730\n\nThe accessed address is 71 bytes into the freed ACL parent, at its\nfeatures[0][3] byte; the queued SCO child is a different object. The\ndiagnostic preserves the loaded parent across the delay, matching the\nunmodified compiled capability check, and does not change the parent\nreferences or teardown path.\n\nHold hci_dev_lock() across the codec switch, including every call to\nfind_next_esco_param(), and release it on all selection errors. Keep\nconfigure_datapath_sync() outside the critical section because it waits\nfor HCI events. Preserve parameter selection and existing return values."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"48bf3b94c7331e11eaa6c89adc054a7bc7c0382e","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"70b55855eecb428d446344d827bda8725ce8b312","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"1239ef0fa809b5952fca679db3faa3e1c00e1dac","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"cabd58d9bb66d49d481f762ce986173db397435d","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"93a737e4e042f59673cd580d35214f278d7b757d","versionType":"git"},{"version":"e07a06b4eb417f5271d33ce2240e93c62d98b7b4","status":"affected","lessThan":"024e05f73a4c1263d031614bc36700ec135eecb4","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/hci_conn.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/hci_conn.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/48bf3b94c7331e11eaa6c89adc054a7bc7c0382e"},{"url":"https://git.kernel.org/stable/c/70b55855eecb428d446344d827bda8725ce8b312"},{"url":"https://git.kernel.org/stable/c/1239ef0fa809b5952fca679db3faa3e1c00e1dac"},{"url":"https://git.kernel.org/stable/c/cabd58d9bb66d49d481f762ce986173db397435d"},{"url":"https://git.kernel.org/stable/c/93a737e4e042f59673cd580d35214f278d7b757d"},{"url":"https://git.kernel.org/stable/c/024e05f73a4c1263d031614bc36700ec135eecb4"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:39:13.042Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}