{"api_version":"1","generated_at":"2026-08-17T11:25:34+00:00","cve":"CVE-2026-74530","urls":{"html":"https://cve.report/CVE-2026-74530","api":"https://cve.report/api/cve/CVE-2026-74530.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-74530","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-74530"},"summary":{"title":"Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callback","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: hold conn in hci_connect_big_sync() callback\n\nThere is theoretical UAF if the conn is freed while the hci_sync task is\nrunning.\n\nHold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to\nmatch the previous behavior.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-15 13:17:58","updated_at":"2026-08-17 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Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74530","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 024421cf39923927ab2b5fe895d1d922b9abe67f 2d91e6244b69d752503b2d44020d8b0e323dbd38 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 024421cf39923927ab2b5fe895d1d922b9abe67f 56e78b670356caab0b607e8aad4cf819a1909d07 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 620810ac1f7f1133a9ac403e132b3ad6995ddf39 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected ee0586ad64a805eaf1a9a10100e908627a561e34 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 6.12.28 6.13 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the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: hold conn in hci_connect_big_sync() callback\n\nThere is theoretical UAF if the conn is freed while the hci_sync task is\nrunning.\n\nHold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to\nmatch the previous behavior."}],"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 LE ISO BIG Create Sync handling (hci_connect_big_sync), reachable via adjacent BLE traffic that drives HCI events (e.g. HCI_EVT_LE_BIG_INFO_ADV_REPORT through iso_connect_ind) and via local ISO sockets; Bluetooth kernel bugs are scored as Adjacent, not Network.\nAC:L - After 024421cf3992 the path blocks in __hci_cmd_sync_status_sk for up to conn_timeout while only holding a bare hci_conn pointer; an attacker who can open/close an ISO broadcast socket (or race teardown during that wait) controls both sides of the race and can reliably trigger the UAF.\nPR:N - Exploitation does not require root or CAP_NET_ADMIN; adjacent attackers can trigger the vulnerable code through unauthenticated over-the-air BLE broadcasts processed by the kernel HCI layer, and local exploitation only needs standard Bluetooth/ISO socket access available to unprivileged users/apps with Bluetooth permission.\nUI:N - No victim interaction is required beyond attacker-controlled actions such as creating an ISO broadcast listener socket, starting BIG sync, and concurrently closing the socket to free hci_conn while hci_sync work is still running; exploitation does not depend on another user opening files or mounting resources.\nS:U - The use-after-free corrupts kernel heap memory within the Bluetooth/hci_conn subsystem and can lead to local privilege escalation, but it does not cross a VM, IOMMU, or sandbox security boundary into another authority domain.\nC:H - This is a kernel heap use-after-free of struct hci_conn; freed connection objects can be reallocated and read through subsequent dereferences in create_big_complete and hci_le_big_create_sync, providing a standard path to arbitrary kernel memory disclosure.\nI:H - UAF on struct hci_conn allows corrupting connection flags and adjacent heap contents; the structure contains function pointers (cleanup, connect_cfm_cb, disconn_cfm_cb) and is large enough to support heap grooming toward arbitrary write or control-flow hijack.\nA:H - Use-after-free during clear_bit on conn->flags in create_big_complete, or accessing conn fields after teardown during the blocking BIG sync command, can cause kernel oops/panic and repeated disruption; UAF availability impact is rated High per kernel guidance."}]}],"providerMetadata":{"dateUpdated":"2026-08-17T05:48:20.035Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/2d91e6244b69d752503b2d44020d8b0e323dbd38"},{"url":"https://git.kernel.org/stable/c/56e78b670356caab0b607e8aad4cf819a1909d07"}],"title":"Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callback","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-74530","datePublished":"2026-08-15T12:27:45.381Z","dateReserved":"2026-08-15T05:44:03.912Z","dateUpdated":"2026-08-17T05:48:20.035Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-15 13:17:58","lastModifiedDate":"2026-08-17 06:19:49","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":"74530","Ordinal":"1","Title":"Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callbac","CVE":"CVE-2026-74530","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"74530","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_sync: hold conn in hci_connect_big_sync() callback\n\nThere is theoretical UAF if the conn is freed while the hci_sync task is\nrunning.\n\nHold refcount to avoid that. Handle NULL hcon, return 0 + do nothing to\nmatch the previous behavior.","Type":"Description","Title":"Bluetooth: hci_sync: hold conn in hci_connect_big_sync() callbac"}]}}}