{"api_version":"1","generated_at":"2026-08-17T11:25:35+00:00","cve":"CVE-2026-74534","urls":{"html":"https://cve.report/CVE-2026-74534","api":"https://cve.report/api/cve/CVE-2026-74534.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74534","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74534"},"summary":{"title":"Bluetooth: ISO: fix refcounting of iso_conn","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: fix refcounting of iso_conn\n\niso_conn_del() and iso_chan_del() have a race that results to double-put\nof iso_conn:\n\n    [Task hdev->workqueue]         [Task 2]\n    iso_conn_del                   iso_chan_del\n      iso_conn_hold_unless_zero      iso_conn_lock\n      iso_conn_lock                  conn->sk = NULL\n                                     iso_conn_unlock\n      sk = iso_sock_hold(conn)  <---------´\n      if (!sk) iso_conn_put          iso_conn_put\n      iso_conn_put /* UAF */\n\nThe extra put for !sk in iso_conn_del() is currently required since\nfailing iso_chan_add() may leave iso_conn not associated with any sk.\n\nFix by having iso_pi(sk)->conn own refcount when non-NULL, so\niso_conn_del does not need to put it.  Adjust the iso_conn_add()\nrefcounting so that conn is put if it does not get associated with an\nsk.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 13:17:58","updated_at":"2026-08-17 06:19:50"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"8.8","severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/3b921533e8aa95b77aadcf31737595578e735f3c","name":"https://git.kernel.org/stable/c/3b921533e8aa95b77aadcf31737595578e735f3c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/fdfde532ab1caa165fcd8985001157ac8b4db365","name":"https://git.kernel.org/stable/c/fdfde532ab1caa165fcd8985001157ac8b4db365","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/8208b4939afb0a1977fffe902c3ca42fe0f3baaa","name":"https://git.kernel.org/stable/c/8208b4939afb0a1977fffe902c3ca42fe0f3baaa","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-74534","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74534","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc26097bdb864a0d5955b9a25e43376ffc1af99b 3b921533e8aa95b77aadcf31737595578e735f3c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc26097bdb864a0d5955b9a25e43376ffc1af99b 8208b4939afb0a1977fffe902c3ca42fe0f3baaa git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected dc26097bdb864a0d5955b9a25e43376ffc1af99b fdfde532ab1caa165fcd8985001157ac8b4db365 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected f53e7489273dc2bb307bf50f319b3762d45534f0 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a58d0f5dac322e16cc75334d000666512341bde5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.11.11 6.12 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.2 6.13 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.13","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.13 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.44 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.8 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"74534","cve":"CVE-2026-74534","epss":"0.001660000","percentile":"0.062810000","score_date":"2026-08-16","updated_at":"2026-08-17 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the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: fix refcounting of iso_conn\n\niso_conn_del() and iso_chan_del() have a race that results to double-put\nof iso_conn:\n\n    [Task hdev->workqueue]         [Task 2]\n    iso_conn_del                   iso_chan_del\n      iso_conn_hold_unless_zero      iso_conn_lock\n      iso_conn_lock                  conn->sk = NULL\n                                     iso_conn_unlock\n      sk = iso_sock_hold(conn)  <---------´\n      if (!sk) iso_conn_put          iso_conn_put\n      iso_conn_put /* UAF */\n\nThe extra put for !sk in iso_conn_del() is currently required since\nfailing iso_chan_add() may leave iso_conn not associated with any sk.\n\nFix by having iso_pi(sk)->conn own refcount when non-NULL, so\niso_conn_del does not need to put it.  Adjust the iso_conn_add()\nrefcounting so that conn is put if it does not get associated with an\nsk."}],"metrics":[{"cvssV3_1":{"baseScore":8.8,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:A - The bug is in Bluetooth ISO connection teardown; a remote LE Audio/CIS/BIS peer in range can trigger iso_conn_del via HCI disconnect events (iso_disconn_cfm) that race with concurrent socket teardown.\nAC:L - The double kref_put race is between iso_conn_del and iso_chan_del; an adjacent attacker controls disconnect timing and can repeatedly connect/disconnect to race automatic kernel and Bluetooth daemon socket cleanup.\nPR:N - No local UNIX privileges are required; a malicious or compromised adjacent Bluetooth ISO peer with an established connection can initiate the disconnect leg without root, capabilities, or user-namespace admin rights.\nUI:N - No explicit victim action is needed beyond an active ISO session; remote disconnect triggers automatic HCI teardown and stack socket close that can race iso_chan_del without the user manually closing applications.\nS:U - The vulnerability corrupts kernel heap lifetime of iso_conn objects within the Bluetooth subsystem and does not cross VM, hypervisor, or IOMMU security boundaries.\nC:H - Premature kfree of iso_conn from the refcount race is a use-after-free that can expose kernel heap contents and be leveraged for arbitrary kernel memory disclosure.\nI:H - UAF on iso_conn enables heap grooming and corrupted pointer dereferences that can be leveraged for arbitrary kernel memory writes or privilege-escalating code execution.\nA:H - The double iso_conn_put can free iso_conn while still referenced, causing kernel oops/panic or reliably exploitable instability during ISO connection teardown."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:48:23.337Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/3b921533e8aa95b77aadcf31737595578e735f3c"},{"url":"https://git.kernel.org/stable/c/8208b4939afb0a1977fffe902c3ca42fe0f3baaa"},{"url":"https://git.kernel.org/stable/c/fdfde532ab1caa165fcd8985001157ac8b4db365"}],"title":"Bluetooth: ISO: fix refcounting of iso_conn","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74534","datePublished":"2026-08-15T12:27:47.831Z","dateReserved":"2026-08-15T05:44:03.913Z","dateUpdated":"2026-08-17T05:48:23.337Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 13:17:58","lastModifiedDate":"2026-08-17 06:19:50","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":2.8,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"74534","Ordinal":"1","Title":"Bluetooth: ISO: fix refcounting of iso_conn","CVE":"CVE-2026-74534","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74534","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: fix refcounting of iso_conn\n\niso_conn_del() and iso_chan_del() have a race that results to double-put\nof iso_conn:\n\n    [Task hdev->workqueue]         [Task 2]\n    iso_conn_del                   iso_chan_del\n      iso_conn_hold_unless_zero      iso_conn_lock\n      iso_conn_lock                  conn->sk = NULL\n                                     iso_conn_unlock\n      sk = iso_sock_hold(conn)  <---------´\n      if (!sk) iso_conn_put          iso_conn_put\n      iso_conn_put /* UAF */\n\nThe extra put for !sk in iso_conn_del() is currently required since\nfailing iso_chan_add() may leave iso_conn not associated with any sk.\n\nFix by having iso_pi(sk)->conn own refcount when non-NULL, so\niso_conn_del does not need to put it.  Adjust the iso_conn_add()\nrefcounting so that conn is put if it does not get associated with an\nsk.","Type":"Description","Title":"Bluetooth: ISO: fix refcounting of iso_conn"}]}}}