{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64557", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.796Z", "datePublished": "2026-07-29T08:01:47.462Z", "dateUpdated": "2026-08-17T04:57:35.594Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:57:35.594Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()\n\nl2cap_sock_new_connection_cb() returned l2cap_pi(sk)->chan after\nrelease_sock(parent). Once the parent lock is dropped the newly\nenqueued child socket sk is reachable via the accept queue, so another\ntask can accept and free it before the callback dereferences sk,\nresulting in a use-after-free.\n\nRework the ->new_connection() op so the core, rather than the callback,\nowns the child channel's lifetime. The op now receives a pre-allocated\nnew_chan and returns an errno instead of allocating and returning a\nchannel. l2cap_new_connection() allocates the child channel and links\nit into the conn list via __l2cap_chan_add() before invoking the\ncallback, so the conn-list reference keeps the channel alive once\nrelease_sock(parent) exposes the socket to other tasks.\n\nChannel configuration that was duplicated in l2cap_sock_init() and the\nvarious new_connection callbacks is consolidated into\nl2cap_chan_set_defaults(), which now inherits from the parent channel\nwhen one is supplied." } ], "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 callback is reached only from L2CAP signalling handlers (`l2cap_connect`, `l2cap_le_connect_req`, `l2cap_ecred_conn_req`, `l2cap_connect_cfm`) processing connection requests received from a remote Bluetooth peer. Bluetooth radio range constitutes an adjacent network.\nAC:L - The attacker drives one side of the race by sending unlimited L2CAP connect requests and can induce the other side, since the local daemon accepts (immediately, for DEFER_SETUP listeners) and closes rejected/unauthorized children; on SMP the accepting task runs truly concurrently while the callback is still inside `release_sock()`, so the window is hit reliably with repeated attempts.\nPR:N - `l2cap_connect()` bypasses the link-mode and encryption-key-size checks entirely for PSM 0x0001 (SDP), where bluetoothd holds a listening L2CAP socket, so an unpaired and unauthenticated remote device can reach `l2cap_sock_new_connection_cb()`; LE CoC and low-security BR/EDR listeners are likewise reachable without credentials.\nUI:N - Incoming L2CAP connection requests are processed automatically by the kernel and accepted by the always-running Bluetooth daemon with no victim action, no pairing prompt, and no user confirmation.\nS:U - The corrupted `l2cap_chan`/`sock` objects and the resulting memory corruption are confined to the kernel's own security authority, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - This is a use-after-free: the freed `l2cap_chan` slab object can be reallocated with attacker-groomed data and its fields are subsequently read back and transmitted to the attacker via the connect response and `l2cap_build_conf_req()`, and `__l2cap_chan_add()` deposits kernel list pointers into the reallocated object, giving a kernel-memory disclosure primitive.\nI:H - After the free, `l2cap_connect()`/`l2cap_le_connect_req()` write attacker-supplied PSM, SCID, MTU/MPS and BD_ADDR values plus list pointers into the freed object, and `__set_chan_timer()` arms delayed work whose function pointers live in that freed memory — a controlled write primitive suitable for heap spraying and control-flow hijack.\nA:H - Even without successful exploitation, the use-after-free reads and writes into freed slab memory and links a dead object into the conn list, reliably producing kernel oops/panic and corrupted list traversal on subsequent L2CAP operations." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/bluetooth/l2cap.h", "net/bluetooth/6lowpan.c", "net/bluetooth/l2cap_core.c", "net/bluetooth/l2cap_sock.c", "net/bluetooth/smp.c" ], "versions": [ { "version": "8ffb929098a56939ac71509302eeab5b207bf262", "lessThan": "b39298044e5534612511a2ff5de03ba5f6e7a820", "status": "affected", "versionType": "git" }, { "version": "8ffb929098a56939ac71509302eeab5b207bf262", "lessThan": "8c37e4338c801ebb8cee52436c01c41e009f6e87", "status": "affected", "versionType": "git" }, { "version": "8ffb929098a56939ac71509302eeab5b207bf262", "lessThan": "84e718b6a814edc84159361f9f454a4e92ae91ae", "status": "affected", "versionType": "git" }, { "version": "8ffb929098a56939ac71509302eeab5b207bf262", "lessThan": "36da806f7fbaee56ad9e81859deec203f9728700", "status": "affected", "versionType": "git" }, { "version": "8ffb929098a56939ac71509302eeab5b207bf262", "lessThan": "733e76e74e406c1d1ddc7369420dd8a47f48bb8a", "status": "affected", "versionType": "git" }, { "version": "8ffb929098a56939ac71509302eeab5b207bf262", "lessThan": "6fef032af0092ed5ccb767239a9ac1bc38c08a40", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/net/bluetooth/l2cap.h", "net/bluetooth/6lowpan.c", "net/bluetooth/l2cap_core.c", "net/bluetooth/l2cap_sock.c", "net/bluetooth/smp.c" ], "versions": [ { "version": "3.13", "status": "affected" }, { "version": "0", "lessThan": "3.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.178", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.97", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.40", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.5", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.1.178" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.6.145" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.12.97" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "6.18.40" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "7.1.5" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.13", "versionEndExcluding": "7.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/b39298044e5534612511a2ff5de03ba5f6e7a820" }, { "url": "https://git.kernel.org/stable/c/8c37e4338c801ebb8cee52436c01c41e009f6e87" }, { "url": "https://git.kernel.org/stable/c/84e718b6a814edc84159361f9f454a4e92ae91ae" }, { "url": "https://git.kernel.org/stable/c/36da806f7fbaee56ad9e81859deec203f9728700" }, { "url": "https://git.kernel.org/stable/c/733e76e74e406c1d1ddc7369420dd8a47f48bb8a" }, { "url": "https://git.kernel.org/stable/c/6fef032af0092ed5ccb767239a9ac1bc38c08a40" } ], "title": "Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()", "x_generator": { "engine": "bippy-1.2.0" } } } }