{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-98108", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.316Z", "datePublished": "2026-09-25T10:35:56.935Z", "dateUpdated": "2026-10-19T09:14:00.739Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:14:00.739Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: fix chan mode for LE_CONN_REQ + EXT_FLOWCTL pchan\n\nl2cap_new_connection() sets default value of channel mode to match the\nparent channel. l2cap_le_connect_req() left this at the default, and\ncreated L2CAP_MODE_EXT_FLOWCTL channels if listening pchan has that\nmode. This causes FLAG_DEFER_SETUP channels to reply to\nL2CAP_LE_CONN_REQ with L2CAP_ECRED_CONN_RSP, which is incorrect.\n\nIt can also result to stack OOB write (of l2cap_alloc_cid determined\nvalues) in l2cap_ecred_rsp_defer(), as l2cap_le_connect_req() does not\nlimit maximum number of deferred channels or check for duplicate ident.\n\nFix by setting chan->mode correctly in l2cap_le_connect_req().\n\nAlso check channel mode in l2cap_ecred_rsp_defer(), and do WARN_ON_ONCE\ninstead of OOB write to make it less brittle." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:A - The malformed input is a series of L2CAP_LE_CONN_REQ signalling commands, all using the same ident, sent over a BLE link to l2cap_le_connect_req(). The attacker must be within Bluetooth radio range, so the vector is Adjacent.\nAC:H - The OOB write only happens if the target runs an LE listener in BT_MODE_EXT_FLOWCTL with DEFER_SETUP, whose children inherit EXT_FLOWCTL through l2cap_new_connection(). The attacker cannot create that listener. Once it exists, the attacker controls how many LE_CONN_REQs share one ident, and the service's own recvmsg() triggers the write.\nPR:N - l2cap_le_connect_req() only checks the listener's sec_level through smp_sufficient_security(). An LE listener defaults to BT_SECURITY_LOW, so an unpaired peer can open the channels, and Just Works pairing is available otherwise.\nUI:N - No human action is needed. The listening service's normal accept/recvmsg on a deferred child calls l2cap_sock_recvmsg(), which then calls __l2cap_ecred_conn_rsp_defer().\nS:U - The memory corruption stays within the kernel's own security authority. No VM or hardware isolation boundary is crossed.\nC:H - l2cap_ecred_rsp_defer() writes CIDs past the 5-entry scid[] into the adjacent 'count' field, which then steers later writes to attacker-influenced offsets on the kernel stack. Corruption of this kind can be leveraged for disclosure.\nI:H - This is an out-of-bounds write on the kernel stack in __l2cap_ecred_conn_rsp_defer(). The written values are l2cap_alloc_cid() CIDs whose count and order the attacker influences, and the write can reach the saved frame state.\nA:H - Stack corruption in __l2cap_ecred_conn_rsp_defer() causes a stack-protector panic or an oops, crashing the kernel, and the peer can repeat it." } ] } ], "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": "15f02b91056253e8cdc592888f431da0731337b8", "lessThan": "ad0f44a3f1f688558ed876a0702bc2c82b0df689", "status": "affected", "versionType": "git" }, { "version": "15f02b91056253e8cdc592888f431da0731337b8", "lessThan": "564ae0e05e598aa895b9dbd18cb7d6eb64752869", "status": "affected", "versionType": "git" }, { "version": "15f02b91056253e8cdc592888f431da0731337b8", "lessThan": "aab17938998b29e75c3324763411aef3e300fc67", "status": "affected", "versionType": "git" }, { "version": "15f02b91056253e8cdc592888f431da0731337b8", "lessThan": "0e1fc7cab95ad958e55d70a5dfaaea687c9c639f", "status": "affected", "versionType": "git" }, { "version": "15f02b91056253e8cdc592888f431da0731337b8", "lessThan": "1074bcc57f741223f9fa82ce6afe5c3d783e4d10", "status": "affected", "versionType": "git" }, { "version": "15f02b91056253e8cdc592888f431da0731337b8", "lessThan": "5d5a625cbc854d4c4f68e4b16fcf6e682d9a9ed1", "status": "affected", "versionType": "git" }, { "version": "15f02b91056253e8cdc592888f431da0731337b8", "lessThan": "6cb79e6499228cfdbd4b3301371ce74d01cd2f80", "status": "affected", "versionType": "git" }, { "version": "15f02b91056253e8cdc592888f431da0731337b8", "lessThan": "4ef05db5b08b176a551b4a6287372045998806b0", "status": "affected", "versionType": "git" } ] }, { "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": "5.7", "status": "affected" }, { "version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.271", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.222", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.158", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.111", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.53", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.7", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "5.7", "versionEndExcluding": "5.10.271" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.15.222" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.1.189" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.6.158" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.12.111" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.18.53" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.2.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/ad0f44a3f1f688558ed876a0702bc2c82b0df689" }, { "url": "https://git.kernel.org/stable/c/564ae0e05e598aa895b9dbd18cb7d6eb64752869" }, { "url": "https://git.kernel.org/stable/c/aab17938998b29e75c3324763411aef3e300fc67" }, { "url": "https://git.kernel.org/stable/c/0e1fc7cab95ad958e55d70a5dfaaea687c9c639f" }, { "url": "https://git.kernel.org/stable/c/1074bcc57f741223f9fa82ce6afe5c3d783e4d10" }, { "url": "https://git.kernel.org/stable/c/5d5a625cbc854d4c4f68e4b16fcf6e682d9a9ed1" }, { "url": "https://git.kernel.org/stable/c/6cb79e6499228cfdbd4b3301371ce74d01cd2f80" }, { "url": "https://git.kernel.org/stable/c/4ef05db5b08b176a551b4a6287372045998806b0" } ], "title": "Bluetooth: L2CAP: fix chan mode for LE_CONN_REQ + EXT_FLOWCTL pchan", "x_generator": { "engine": "bippy-1.2.0" } } } }