{"api_version":"1","generated_at":"2026-07-23T20:40:40+00:00","cve":"CVE-2026-63944","urls":{"html":"https://cve.report/CVE-2026-63944","api":"https://cve.report/api/cve/CVE-2026-63944.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63944","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63944"},"summary":{"title":"Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix UAF in hci_le_create_cis_sync\n\nhci_le_create_cis_sync() dereferences conn->conn_timeout after releasing\nboth rcu_read_lock() and hci_dev_lock(hdev).  The conn pointer was\nobtained from an RCU-protected iteration over hdev->conn_hash.list and\nis not valid once these locks are dropped.  A concurrent disconnect can\nfree the hci_conn between the unlock and the dereference, causing a\nuse-after-free read.\n\nThe cancellation mechanism in hci_conn_del() cannot prevent this because\nhci_le_create_cis_pending() queues hci_create_cis_sync with data=NULL:\n\n    hci_cmd_sync_queue(hdev, hci_create_cis_sync, NULL, NULL);\n\nWhile hci_conn_del() dequeues with data=conn:\n\n    hci_cmd_sync_dequeue(hdev, NULL, conn, NULL);\n\nSince NULL != conn, the lookup in _hci_cmd_sync_lookup_entry() never\nmatches, and the pending work item is not cancelled.\n\nFix this by saving conn->conn_timeout into a local variable while the\nlocks are still held, so the stale conn pointer is never dereferenced\nafter unlock.\n\nThis is the same class of bug as the one fixed by commit 035c25007c9e\n(\"Bluetooth: hci_sync: Fix UAF on le_read_features_complete\") which\naddressed the identical pattern in a different function.\n\nThis vulnerability was identified using 0sec.ai, an open-source\nautomated security auditing platform (https://github.com/0sec-labs).","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:12","updated_at":"2026-07-20 15:16:58"},"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/380e67b1794a9a281a0cb592b4e62077fbd0c8ca","name":"https://git.kernel.org/stable/c/380e67b1794a9a281a0cb592b4e62077fbd0c8ca","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a921957d39290143629eb38c4f74b9bef8035d0a","name":"https://git.kernel.org/stable/c/a921957d39290143629eb38c4f74b9bef8035d0a","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a55618c0f4cead9e59c63f5ee030d393fd70d861","name":"https://git.kernel.org/stable/c/a55618c0f4cead9e59c63f5ee030d393fd70d861","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bfea6091e0fffb270c20e74384b660910277eb6c","name":"https://git.kernel.org/stable/c/bfea6091e0fffb270c20e74384b660910277eb6c","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d9019210c8c30d40eb20094274cc647e352f48f7","name":"https://git.kernel.org/stable/c/d9019210c8c30d40eb20094274cc647e352f48f7","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63944","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63944","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c09b80be6ffc338634b2f5f8cfa12b6843410834 a55618c0f4cead9e59c63f5ee030d393fd70d861 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c09b80be6ffc338634b2f5f8cfa12b6843410834 a921957d39290143629eb38c4f74b9bef8035d0a git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c09b80be6ffc338634b2f5f8cfa12b6843410834 d9019210c8c30d40eb20094274cc647e352f48f7 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c09b80be6ffc338634b2f5f8cfa12b6843410834 380e67b1794a9a281a0cb592b4e62077fbd0c8ca git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected c09b80be6ffc338634b2f5f8cfa12b6843410834 bfea6091e0fffb270c20e74384b660910277eb6c git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.4","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.4 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.143 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.93 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.35 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.12 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"63944","cve":"CVE-2026-63944","epss":"0.002000000","percentile":"0.100190000","score_date":"2026-07-20","updated_at":"2026-07-21 00:13:13"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/bluetooth/hci_sync.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"a55618c0f4cead9e59c63f5ee030d393fd70d861","status":"affected","version":"c09b80be6ffc338634b2f5f8cfa12b6843410834","versionType":"git"},{"lessThan":"a921957d39290143629eb38c4f74b9bef8035d0a","status":"affected","version":"c09b80be6ffc338634b2f5f8cfa12b6843410834","versionType":"git"},{"lessThan":"d9019210c8c30d40eb20094274cc647e352f48f7","status":"affected","version":"c09b80be6ffc338634b2f5f8cfa12b6843410834","versionType":"git"},{"lessThan":"380e67b1794a9a281a0cb592b4e62077fbd0c8ca","status":"affected","version":"c09b80be6ffc338634b2f5f8cfa12b6843410834","versionType":"git"},{"lessThan":"bfea6091e0fffb270c20e74384b660910277eb6c","status":"affected","version":"c09b80be6ffc338634b2f5f8cfa12b6843410834","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/bluetooth/hci_sync.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"6.4"},{"lessThan":"6.4","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.143","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.93","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.35","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.12","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.143","versionStartIncluding":"6.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.93","versionStartIncluding":"6.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.35","versionStartIncluding":"6.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.12","versionStartIncluding":"6.4","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"6.4","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix UAF in hci_le_create_cis_sync\n\nhci_le_create_cis_sync() dereferences conn->conn_timeout after releasing\nboth rcu_read_lock() and hci_dev_lock(hdev).  The conn pointer was\nobtained from an RCU-protected iteration over hdev->conn_hash.list and\nis not valid once these locks are dropped.  A concurrent disconnect can\nfree the hci_conn between the unlock and the dereference, causing a\nuse-after-free read.\n\nThe cancellation mechanism in hci_conn_del() cannot prevent this because\nhci_le_create_cis_pending() queues hci_create_cis_sync with data=NULL:\n\n    hci_cmd_sync_queue(hdev, hci_create_cis_sync, NULL, NULL);\n\nWhile hci_conn_del() dequeues with data=conn:\n\n    hci_cmd_sync_dequeue(hdev, NULL, conn, NULL);\n\nSince NULL != conn, the lookup in _hci_cmd_sync_lookup_entry() never\nmatches, and the pending work item is not cancelled.\n\nFix this by saving conn->conn_timeout into a local variable while the\nlocks are still held, so the stale conn pointer is never dereferenced\nafter unlock.\n\nThis is the same class of bug as the one fixed by commit 035c25007c9e\n(\"Bluetooth: hci_sync: Fix UAF on le_read_features_complete\") which\naddressed the identical pattern in a different function.\n\nThis vulnerability was identified using 0sec.ai, an open-source\nautomated security auditing platform (https://github.com/0sec-labs)."}],"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"}}],"providerMetadata":{"dateUpdated":"2026-07-20T13:41:45.061Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/a55618c0f4cead9e59c63f5ee030d393fd70d861"},{"url":"https://git.kernel.org/stable/c/a921957d39290143629eb38c4f74b9bef8035d0a"},{"url":"https://git.kernel.org/stable/c/d9019210c8c30d40eb20094274cc647e352f48f7"},{"url":"https://git.kernel.org/stable/c/380e67b1794a9a281a0cb592b4e62077fbd0c8ca"},{"url":"https://git.kernel.org/stable/c/bfea6091e0fffb270c20e74384b660910277eb6c"}],"title":"Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63944","datePublished":"2026-07-19T14:55:39.105Z","dateReserved":"2026-07-19T07:54:57.022Z","dateUpdated":"2026-07-20T13:41:45.061Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:12","lastModifiedDate":"2026-07-20 15:16:58","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":"63944","Ordinal":"1","Title":"Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync","CVE":"CVE-2026-63944","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63944","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: fix UAF in hci_le_create_cis_sync\n\nhci_le_create_cis_sync() dereferences conn->conn_timeout after releasing\nboth rcu_read_lock() and hci_dev_lock(hdev).  The conn pointer was\nobtained from an RCU-protected iteration over hdev->conn_hash.list and\nis not valid once these locks are dropped.  A concurrent disconnect can\nfree the hci_conn between the unlock and the dereference, causing a\nuse-after-free read.\n\nThe cancellation mechanism in hci_conn_del() cannot prevent this because\nhci_le_create_cis_pending() queues hci_create_cis_sync with data=NULL:\n\n    hci_cmd_sync_queue(hdev, hci_create_cis_sync, NULL, NULL);\n\nWhile hci_conn_del() dequeues with data=conn:\n\n    hci_cmd_sync_dequeue(hdev, NULL, conn, NULL);\n\nSince NULL != conn, the lookup in _hci_cmd_sync_lookup_entry() never\nmatches, and the pending work item is not cancelled.\n\nFix this by saving conn->conn_timeout into a local variable while the\nlocks are still held, so the stale conn pointer is never dereferenced\nafter unlock.\n\nThis is the same class of bug as the one fixed by commit 035c25007c9e\n(\"Bluetooth: hci_sync: Fix UAF on le_read_features_complete\") which\naddressed the identical pattern in a different function.\n\nThis vulnerability was identified using 0sec.ai, an open-source\nautomated security auditing platform (https://github.com/0sec-labs).","Type":"Description","Title":"Bluetooth: hci_sync: fix UAF in hci_le_create_cis_sync"}]}}}