{"id":"CVE-2024-56591","state":"PUBLISHED","title":"Bluetooth: hci_conn: Use disable_delayed_work_sync","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_conn: Use disable_delayed_work_sync\n\nThis makes use of disable_delayed_work_sync instead\ncancel_delayed_work_sync as it not only cancel the ongoing work but also\ndisables new submit which is disarable since the object holding the work\nis about to be freed.","publishedAt":"2024-12-27T14:50:58.674Z","updatedAt":"2026-08-05T11:45:13.959Z","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":"19c40e3bcaf2d969f5d4ee85bbe1330b54d36d9c","status":"affected","lessThan":"c55a4c5a04bae40dcdc1e1c19d8eb79a06fb3397","versionType":"git"},{"version":"19c40e3bcaf2d969f5d4ee85bbe1330b54d36d9c","status":"affected","lessThan":"2b0f2fc9ed62e73c95df1fa8ed2ba3dac54699df","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":"3.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.3","versionType":"semver"},{"version":"6.12.5","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13","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/c55a4c5a04bae40dcdc1e1c19d8eb79a06fb3397","https://git.kernel.org/stable/c/2b0f2fc9ed62e73c95df1fa8ed2ba3dac54699df"],"weaknesses":[],"ingestedAt":"2026-10-29T20:08:12.933Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2024/56xxx/CVE-2024-56591.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-56591","state":"PUBLISHED","datePublished":"2024-12-27T14:50:58.674Z","dateUpdated":"2026-08-05T11:45:13.959Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-12-27T14:03:06.003Z"},"containers":{"cna":{"title":"Bluetooth: hci_conn: Use disable_delayed_work_sync","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_conn: Use disable_delayed_work_sync\n\nThis makes use of disable_delayed_work_sync instead\ncancel_delayed_work_sync as it not only cancel the ongoing work but also\ndisables new submit which is disarable since the object holding the work\nis about to be freed."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"19c40e3bcaf2d969f5d4ee85bbe1330b54d36d9c","status":"affected","lessThan":"c55a4c5a04bae40dcdc1e1c19d8eb79a06fb3397","versionType":"git"},{"version":"19c40e3bcaf2d969f5d4ee85bbe1330b54d36d9c","status":"affected","lessThan":"2b0f2fc9ed62e73c95df1fa8ed2ba3dac54699df","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":"3.3","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.3","versionType":"semver"},{"version":"6.12.5","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.13","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/c55a4c5a04bae40dcdc1e1c19d8eb79a06fb3397"},{"url":"https://git.kernel.org/stable/c/2b0f2fc9ed62e73c95df1fa8ed2ba3dac54699df"}],"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 vulnerable teardown path lives in the Bluetooth HCI connection layer and is driven by connection setup/disconnect events from a peer device, so the attacker must be within Bluetooth radio range of the target. Per kernel scoring convention Bluetooth reachability is Adjacent.\nAC:L - Although this is a race, the attacker controls both sides of it — repeatedly initiating and abruptly dropping L2CAP/LE connections drives `hci_conn_del()` on the HCI event path while concurrent channel teardown calls `hci_conn_drop()` and re-arms `disc_work`. The attempt can be retried indefinitely with no condition outside the attacker's influence.\nPR:N - No privileges on the target are required: L2CAP/LE connection establishment and teardown occur before pairing or authentication, and no capability check exists anywhere on the path from packet/event handling to `hci_conn_del()`.\nUI:N - The entire sequence is driven by attacker-initiated link establishment and disconnection handled automatically by the kernel's HCI event processing. No action by a local user or victim is needed.\nS:U - The use-after-free corrupts kernel heap memory within the same kernel security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The re-armed delayed work leaves an armed timer and workqueue linkage inside a freed `hci_conn` slab object, and `hci_conn_timeout()`/`hci_conn_idle()` subsequently read attacker-groomed reallocated memory. This use-after-free gives an arbitrary kernel read primitive and can leak arbitrary kernel memory.\nI:H - `queue_delayed_work()`/`cancel_delayed_work()` write into the freed object, and the pending timer's `->function` and the work's `->func` are later dereferenced out of it, so heap spraying yields a controlled write and an indirect call — sufficient for control-flow hijack and kernel privilege escalation.\nA:H - Even unexploited, the use-after-free dereferences freed slab memory from timer softirq and workqueue context, producing KASAN splats, oopses, or a kernel panic, which syzbot reproduced reliably."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T11:45:13.959Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"6.12.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.3","versionEndExcluding":"6.13"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}