{"id":"CVE-2026-74535","state":"PUBLISHED","title":"Bluetooth: ISO: avoid deadlocks in iso_sock_timeout","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: avoid deadlocks in iso_sock_timeout\n\niso_sock_timeout() takes lock_sock, so sync disabling the timer while\nholding that lock may deadlock.\n\niso_sock_timeout() may also run concurrently with iso_conn_del(), which\nleads to UAF\n\n        [Task 1]                      [Task hdev->workqueue]\n        iso_sock_timeout              iso_conn_del\n          iso_conn_hold_unless_zero     iso_chan_del\n                           `------------> iso_conn_put\n                                      caller frees hcon\n          iso_conn_put\n            iso_conn_free\n              conn->hcon->iso_data = NULL; /* UAF */\n\nFix the deadlock by removing the disable from the lock_sock sections.\nMove the timer from iso_conn to iso_pinfo to decouple it from iso_conn\nwhich may need to be freed in lock_sock section. Convert some of the\nclear_timer to disable_timer.","publishedAt":"2026-08-15T12:27:48.449Z","updatedAt":"2026-10-16T19:05:53.982Z","severity":{"score":8.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a58d0f5dac322e16cc75334d000666512341bde5","status":"affected","lessThan":"16d89a63e08280abeef7218970a3bbd7ca62b021","versionType":"git"},{"version":"dc26097bdb864a0d5955b9a25e43376ffc1af99b","status":"affected","lessThan":"82e982f54f962f72646868ddbb2c3bd9ea178568","versionType":"git"},{"version":"dc26097bdb864a0d5955b9a25e43376ffc1af99b","status":"affected","lessThan":"3c3d5f85db80145636bb991a6005e2760012b985","versionType":"git"},{"version":"dc26097bdb864a0d5955b9a25e43376ffc1af99b","status":"affected","lessThan":"200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43","versionType":"git"},{"version":"f53e7489273dc2bb307bf50f319b3762d45534f0","status":"affected","versionType":"git"},{"version":"6.12.2","status":"affected","lessThan":"6.12.103","versionType":"semver"},{"version":"6.11.11","status":"affected","lessThan":"6.12","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/iso.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.13","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/iso.c"]}],"references":["https://git.kernel.org/stable/c/16d89a63e08280abeef7218970a3bbd7ca62b021","https://git.kernel.org/stable/c/82e982f54f962f72646868ddbb2c3bd9ea178568","https://git.kernel.org/stable/c/3c3d5f85db80145636bb991a6005e2760012b985","https://git.kernel.org/stable/c/200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74535.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74535","state":"PUBLISHED","datePublished":"2026-08-15T12:27:48.449Z","dateUpdated":"2026-10-16T19:05:53.982Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.913Z"},"containers":{"cna":{"title":"Bluetooth: ISO: avoid deadlocks in iso_sock_timeout","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: avoid deadlocks in iso_sock_timeout\n\niso_sock_timeout() takes lock_sock, so sync disabling the timer while\nholding that lock may deadlock.\n\niso_sock_timeout() may also run concurrently with iso_conn_del(), which\nleads to UAF\n\n        [Task 1]                      [Task hdev->workqueue]\n        iso_sock_timeout              iso_conn_del\n          iso_conn_hold_unless_zero     iso_chan_del\n                           `------------> iso_conn_put\n                                      caller frees hcon\n          iso_conn_put\n            iso_conn_free\n              conn->hcon->iso_data = NULL; /* UAF */\n\nFix the deadlock by removing the disable from the lock_sock sections.\nMove the timer from iso_conn to iso_pinfo to decouple it from iso_conn\nwhich may need to be freed in lock_sock section. Convert some of the\nclear_timer to disable_timer."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a58d0f5dac322e16cc75334d000666512341bde5","status":"affected","lessThan":"16d89a63e08280abeef7218970a3bbd7ca62b021","versionType":"git"},{"version":"dc26097bdb864a0d5955b9a25e43376ffc1af99b","status":"affected","lessThan":"82e982f54f962f72646868ddbb2c3bd9ea178568","versionType":"git"},{"version":"dc26097bdb864a0d5955b9a25e43376ffc1af99b","status":"affected","lessThan":"3c3d5f85db80145636bb991a6005e2760012b985","versionType":"git"},{"version":"dc26097bdb864a0d5955b9a25e43376ffc1af99b","status":"affected","lessThan":"200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43","versionType":"git"},{"version":"f53e7489273dc2bb307bf50f319b3762d45534f0","status":"affected","versionType":"git"},{"version":"6.12.2","status":"affected","lessThan":"6.12.103","versionType":"semver"},{"version":"6.11.11","status":"affected","lessThan":"6.12","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/iso.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.13","versionType":"semver"},{"version":"6.12.103","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.44","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.8","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/iso.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/16d89a63e08280abeef7218970a3bbd7ca62b021"},{"url":"https://git.kernel.org/stable/c/82e982f54f962f72646868ddbb2c3bd9ea178568"},{"url":"https://git.kernel.org/stable/c/3c3d5f85db80145636bb991a6005e2760012b985"},{"url":"https://git.kernel.org/stable/c/200fa1629c57a3ca2b03d3ca63fd3a9bfd910c43"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":8.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:A - The bug is in the Bluetooth ISO socket layer (BTPROTO_ISO); iso_sock_timeout and iso_conn_del are reached via HCI disconnect/connect events from an adjacent BLE peer and local ISO socket syscalls, which per kernel guidance is Adjacent not Network.\nAC:L - Exploitation is a race between iso_sock_timeout and iso_conn_del that an attacker can reliably force by controlling ISO connect/disconnect timing and socket send timeouts (SO_SNDTIMEO) on concurrent workqueues, so success does not depend on uncontrollable conditions.\nPR:N - An adjacent Bluetooth attacker can trigger iso_conn_del through remote HCI disconnect/failure events without any credentials or privileges on the victim host; only a normal active or pending ISO/LE Audio session must exist on the target.\nUI:N - No deliberate victim interaction beyond routine Bluetooth/LE Audio operation is required; exploitation can occur in the background while an ISO connection is pending or active, without opening files or performing a separate enabling action.\nS:U - The UAF/deadlock corrupts kernel heap memory on the host and enables local privilege escalation within the kernel security boundary, not a cross-boundary escape such as VM guest-to-host or IOMMU bypass.\nC:H - iso_conn_free dereferences conn->hcon after concurrent iso_conn_del frees the hci_conn (UAF on conn->hcon->iso_data), enabling arbitrary kernel memory read/disclosure through heap corruption per UAF guidance.\nI:H - The UAF permits writes through conn->hcon->iso_data and hci_conn_drop on freed hci_conn memory, providing heap corruption primitives that can be leveraged for arbitrary kernel writes or code execution.\nA:H - The UAF causes kernel oops/panic on freed hci_conn access, and the lock_sock versus disable_delayed_work_sync deadlock in iso_sock_timeout/iso_conn_del paths can hang the system; both crash and deadlock map to High availability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-17T05:48:24.441Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.2","versionEndExcluding":"6.12.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.11.11"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74535","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T18:59:30.482999Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T19:05:53.982Z"}}]}}}