{"id":"CVE-2023-54214","state":"PUBLISHED","title":"Bluetooth: L2CAP: Fix potential user-after-free","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix potential user-after-free\n\nThis fixes all instances of which requires to allocate a buffer calling\nalloc_skb which may release the chan lock and reacquire later which\nmakes it possible that the chan is disconnected in the meantime.","publishedAt":"2025-12-30T12:11:11.383Z","updatedAt":"2026-10-15T21:41:41.834Z","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":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"b2fde8cb2a25125111f2144604e0e7c0ebcc4bba","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"a6a7d1541fefddf7ca0cfb34c1bff63ff809cc49","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"60aaccf16d1e099c16bebfb96428ae762cb528f7","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"b8ed41cc04fb74005aa51d17865ca3d022760335","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"31a288a4df7f6a28e65da22a4ab2add4a963738e","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"64e28ecf44e46de9f01915a4146706a21c3469d2","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"994e3e18908f5c4a12d07b44018e6aa85f071048","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"df5703348813235874d851934e957c3723d71644","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c","net/bluetooth/l2cap_sock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.5","versionType":"semver"},{"version":"4.14.308","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.276","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.235","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.173","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.99","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.16","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.3","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c","net/bluetooth/l2cap_sock.c"]}],"references":["https://git.kernel.org/stable/c/b2fde8cb2a25125111f2144604e0e7c0ebcc4bba","https://git.kernel.org/stable/c/a6a7d1541fefddf7ca0cfb34c1bff63ff809cc49","https://git.kernel.org/stable/c/60aaccf16d1e099c16bebfb96428ae762cb528f7","https://git.kernel.org/stable/c/b8ed41cc04fb74005aa51d17865ca3d022760335","https://git.kernel.org/stable/c/31a288a4df7f6a28e65da22a4ab2add4a963738e","https://git.kernel.org/stable/c/64e28ecf44e46de9f01915a4146706a21c3469d2","https://git.kernel.org/stable/c/994e3e18908f5c4a12d07b44018e6aa85f071048","https://git.kernel.org/stable/c/df5703348813235874d851934e957c3723d71644"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:42.242Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/54xxx/CVE-2023-54214.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-54214","state":"PUBLISHED","datePublished":"2025-12-30T12:11:11.383Z","dateUpdated":"2026-10-15T21:41:41.834Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-12-30T12:06:44.500Z"},"containers":{"cna":{"title":"Bluetooth: L2CAP: Fix potential user-after-free","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix potential user-after-free\n\nThis fixes all instances of which requires to allocate a buffer calling\nalloc_skb which may release the chan lock and reacquire later which\nmakes it possible that the chan is disconnected in the meantime."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"b2fde8cb2a25125111f2144604e0e7c0ebcc4bba","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"a6a7d1541fefddf7ca0cfb34c1bff63ff809cc49","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"60aaccf16d1e099c16bebfb96428ae762cb528f7","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"b8ed41cc04fb74005aa51d17865ca3d022760335","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"31a288a4df7f6a28e65da22a4ab2add4a963738e","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"64e28ecf44e46de9f01915a4146706a21c3469d2","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"994e3e18908f5c4a12d07b44018e6aa85f071048","versionType":"git"},{"version":"a6a5568c03c4805d4d250f6bd9d468eeeb4ea059","status":"affected","lessThan":"df5703348813235874d851934e957c3723d71644","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c","net/bluetooth/l2cap_sock.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.5","versionType":"semver"},{"version":"4.14.308","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.276","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.235","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.173","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.99","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.16","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2.3","status":"unaffected","lessThanOrEqual":"6.2.*","versionType":"semver"},{"version":"6.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c","net/bluetooth/l2cap_sock.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/b2fde8cb2a25125111f2144604e0e7c0ebcc4bba"},{"url":"https://git.kernel.org/stable/c/a6a7d1541fefddf7ca0cfb34c1bff63ff809cc49"},{"url":"https://git.kernel.org/stable/c/60aaccf16d1e099c16bebfb96428ae762cb528f7"},{"url":"https://git.kernel.org/stable/c/b8ed41cc04fb74005aa51d17865ca3d022760335"},{"url":"https://git.kernel.org/stable/c/31a288a4df7f6a28e65da22a4ab2add4a963738e"},{"url":"https://git.kernel.org/stable/c/64e28ecf44e46de9f01915a4146706a21c3469d2"},{"url":"https://git.kernel.org/stable/c/994e3e18908f5c4a12d07b44018e6aa85f071048"},{"url":"https://git.kernel.org/stable/c/df5703348813235874d851934e957c3723d71644"}],"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 window is opened and closed by a remote Bluetooth peer over an L2CAP/RFCOMM/LE CoC connection, which requires only radio proximity to the target. Per kernel scoring convention Bluetooth-reachable bugs are Adjacent.\nAC:L - The attacker controls both sides of the race: withholding L2CAP credits (or ACL buffers) parks the sender in the blocking `bt_skb_send_alloc()` with the chan lock released for an unbounded time, and the attacker then terminates the link to run `l2cap_conn_del()`/`kfree(conn)` inside that window. This makes the race deterministic rather than dependent on timing luck.\nPR:N - No local account and no privileges are needed — the sending side is the kernel's own RFCOMM session or a system Bluetooth daemon, and L2CAP/LE CoC channels at BT_SECURITY_LOW accept connections without pairing or authentication. The attacker is purely an unauthenticated adjacent device.\nUI:N - Exploitation needs only a connectable/discoverable target or an already-established profile connection; the freed-conn dereference happens entirely within normal send and link-teardown handling. No victim action is required.\nS:U - The corruption and its consequences are confined to the kernel's own security authority, with no crossing of a VM, IOMMU, or sandbox boundary. This is a standard in-kernel memory-safety issue.\nC:H - This is a use-after-free read of a freed `struct l2cap_conn` slab object whose contents the attacker can influence by reclaiming the slot with heap spray, and the value read (`conn->mtu`) feeds fragment sizing and copy loops. UAF of an attacker-groomable object is treated as enabling arbitrary read.\nI:H - The dangling `l2cap_conn` is used to drive skb allocation and fragmentation while the freed slab is attacker-reclaimable, giving heap-grooming leverage over subsequent kernel allocations and control-flow-relevant state. Per kernel guidance a use-after-free is scored as exploitable for arbitrary write/control-flow hijack.\nA:H - The freed-object read reliably oopses under any hardening (KASAN/slab poisoning) and, when the reclaimed `conn->mtu` reads as 0, `count` becomes 0 so `len` never decreases — an infinite skb-allocation loop causing hang and memory exhaustion. Either outcome is a full denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T09:18:06.231Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"4.14.308"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"4.19.276"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"5.4.235"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"5.10.173"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"5.15.99"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.1.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.2.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2023-54214","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-15T21:39:26.318408Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-15T21:41:41.834Z"}}]}}}