{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23461", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:46.021Z", "datePublished": "2026-04-03T15:15:41.051Z", "dateUpdated": "2026-08-05T12:21:59.477Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:21:59.477Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user\n\nAfter commit ab4eedb790ca (\"Bluetooth: L2CAP: Fix corrupted list in\nhci_chan_del\"), l2cap_conn_del() uses conn->lock to protect access to\nconn->users. However, l2cap_register_user() and l2cap_unregister_user()\ndon't use conn->lock, creating a race condition where these functions can\naccess conn->users and conn->hchan concurrently with l2cap_conn_del().\n\nThis can lead to use-after-free and list corruption bugs, as reported\nby syzbot.\n\nFix this by changing l2cap_register_user() and l2cap_unregister_user()\nto use conn->lock instead of hci_dev_lock(), ensuring consistent locking\nfor the l2cap_conn structure." } ], "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 L2CAP/HIDP teardown path is reachable through Bluetooth ACL/L2CAP connection handling by a nearby Bluetooth peer. Bluetooth proximity is an adjacent-network attack surface rather than internet-routable network access.\nAC:L - This is a locking/race use-after-free where the attacker can repeatedly drive HIDP/L2CAP connection teardown and unregister paths through connection close/disconnect behavior. The race is not dependent on a rare configuration or a condition outside attacker influence.\nPR:N - Although the local HIDP management ioctl path is gated by init-namespace CAP_NET_ADMIN, an adjacent malicious Bluetooth HID peer can trigger teardown of an already established HIDP/L2CAP session without privileges on the victim system. Under the higher-severity reasonable Bluetooth-peer scenario, no victim-system privileges are required.\nUI:N - Once the HIDP/L2CAP session exists, triggering the vulnerable unregister/connection-delete race does not require a victim user to perform an action. The peer can cause disconnect/teardown behavior directly.\nS:U - The vulnerability corrupts kernel Bluetooth/L2CAP state within the same kernel security authority. It is not a VM escape, IOMMU bypass, or other scope-changing boundary crossing.\nC:H - The flaw is a kernel use-after-free/list corruption condition involving L2CAP connection/user objects and potentially freed HCI device memory. Kernel UAFs are defensibly treated as enabling high confidentiality impact through memory disclosure primitives.\nI:H - The same UAF/list corruption can be leveraged beyond a crash for heap manipulation and control-flow or data-structure corruption. Kernel memory corruption is therefore high integrity impact.\nA:H - Syzbot reports show KASAN use-after-free crashes in l2cap_unregister_user, and the bug can corrupt lists during connection teardown. A kernel crash/oops is high availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bluetooth/l2cap_core.c" ], "versions": [ { "version": "efc30877bd4bc85fefe98d80af60fafc86e5775e", "lessThan": "11a87dd5df428a4b79a84d2790cac7f3c73f1f0d", "status": "affected", "versionType": "git" }, { "version": "f87271d21dd4ee83857ca11b94e7b4952749bbae", "lessThan": "c22a5e659959eb77c2fbb58a5adfaf3c3dab7abf", "status": "affected", "versionType": "git" }, { "version": "ab4eedb790cae44313759b50fe47da285e2519d5", "lessThan": "da3000cbe4851458a22be38bb18c0689c39fdd5f", "status": "affected", "versionType": "git" }, { "version": "ab4eedb790cae44313759b50fe47da285e2519d5", "lessThan": "71030f3b3015a412133a805ff47970cdcf30c2b8", "status": "affected", "versionType": "git" }, { "version": "ab4eedb790cae44313759b50fe47da285e2519d5", "lessThan": "752a6c9596dd25efd6978a73ff21f3b592668f4a", "status": "affected", "versionType": "git" }, { "version": "18ab6b6078fa8191ca30a3065d57bf35d5635761", "status": "affected", "versionType": "git" }, { "version": "6.6.84", "lessThan": "6.6.130", "status": "affected", "versionType": "semver" }, { "version": "6.12.20", "lessThan": "6.12.78", "status": "affected", "versionType": "semver" }, { "version": "6.13.8", "lessThan": "6.14", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bluetooth/l2cap_core.c" ], "versions": [ { "version": "6.14", "status": "affected" }, { "version": "0", "lessThan": "6.14", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.130", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.78", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.20", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.10", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "6.6.84", "versionEndExcluding": "6.6.130" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.20", "versionEndExcluding": "6.12.78" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "6.18.20" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "6.19.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.14", "versionEndExcluding": "7.0" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.13.8" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/11a87dd5df428a4b79a84d2790cac7f3c73f1f0d" }, { "url": "https://git.kernel.org/stable/c/c22a5e659959eb77c2fbb58a5adfaf3c3dab7abf" }, { "url": "https://git.kernel.org/stable/c/da3000cbe4851458a22be38bb18c0689c39fdd5f" }, { "url": "https://git.kernel.org/stable/c/71030f3b3015a412133a805ff47970cdcf30c2b8" }, { "url": "https://git.kernel.org/stable/c/752a6c9596dd25efd6978a73ff21f3b592668f4a" } ], "title": "Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user", "x_generator": { "engine": "bippy-1.2.0" } } } }