{"api_version":"1","generated_at":"2026-10-03T20:33:28+00:00","cve":"CVE-2026-98108","urls":{"html":"https://cve.report/CVE-2026-98108","api":"https://cve.report/api/cve/CVE-2026-98108.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-98108","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-98108"},"summary":{"title":"Bluetooth: L2CAP: fix chan mode for LE_CONN_REQ + EXT_FLOWCTL pchan","description":"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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-09-25 11:17:41","updated_at":"2026-10-03 11:18:32"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"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","attackVector":"ADJACENT_NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","data":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/6cb79e6499228cfdbd4b3301371ce74d01cd2f80","name":"https://git.kernel.org/stable/c/6cb79e6499228cfdbd4b3301371ce74d01cd2f80","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/5d5a625cbc854d4c4f68e4b16fcf6e682d9a9ed1","name":"https://git.kernel.org/stable/c/5d5a625cbc854d4c4f68e4b16fcf6e682d9a9ed1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/4ef05db5b08b176a551b4a6287372045998806b0","name":"https://git.kernel.org/stable/c/4ef05db5b08b176a551b4a6287372045998806b0","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/564ae0e05e598aa895b9dbd18cb7d6eb64752869","name":"https://git.kernel.org/stable/c/564ae0e05e598aa895b9dbd18cb7d6eb64752869","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/aab17938998b29e75c3324763411aef3e300fc67","name":"https://git.kernel.org/stable/c/aab17938998b29e75c3324763411aef3e300fc67","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/0e1fc7cab95ad958e55d70a5dfaaea687c9c639f","name":"https://git.kernel.org/stable/c/0e1fc7cab95ad958e55d70a5dfaaea687c9c639f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1074bcc57f741223f9fa82ce6afe5c3d783e4d10","name":"https://git.kernel.org/stable/c/1074bcc57f741223f9fa82ce6afe5c3d783e4d10","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/ad0f44a3f1f688558ed876a0702bc2c82b0df689","name":"https://git.kernel.org/stable/c/ad0f44a3f1f688558ed876a0702bc2c82b0df689","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-98108","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98108","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 15f02b91056253e8cdc592888f431da0731337b8 ad0f44a3f1f688558ed876a0702bc2c82b0df689 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 15f02b91056253e8cdc592888f431da0731337b8 564ae0e05e598aa895b9dbd18cb7d6eb64752869 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 15f02b91056253e8cdc592888f431da0731337b8 aab17938998b29e75c3324763411aef3e300fc67 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 15f02b91056253e8cdc592888f431da0731337b8 0e1fc7cab95ad958e55d70a5dfaaea687c9c639f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.222 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.189 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.158 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.111 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.53 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2.7 7.2.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.3-rc2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"98108","cve":"CVE-2026-98108","epss":"0.002260000","percentile":"0.119550000","score_date":"2026-09-27","updated_at":"2026-09-28 00:02:23"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["net/bluetooth/l2cap_core.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"ad0f44a3f1f688558ed876a0702bc2c82b0df689","status":"affected","version":"15f02b91056253e8cdc592888f431da0731337b8","versionType":"git"},{"lessThan":"564ae0e05e598aa895b9dbd18cb7d6eb64752869","status":"affected","version":"15f02b91056253e8cdc592888f431da0731337b8","versionType":"git"},{"lessThan":"aab17938998b29e75c3324763411aef3e300fc67","status":"affected","version":"15f02b91056253e8cdc592888f431da0731337b8","versionType":"git"},{"lessThan":"0e1fc7cab95ad958e55d70a5dfaaea687c9c639f","status":"affected","version":"15f02b91056253e8cdc592888f431da0731337b8","versionType":"git"},{"lessThan":"1074bcc57f741223f9fa82ce6afe5c3d783e4d10","status":"affected","version":"15f02b91056253e8cdc592888f431da0731337b8","versionType":"git"},{"lessThan":"5d5a625cbc854d4c4f68e4b16fcf6e682d9a9ed1","status":"affected","version":"15f02b91056253e8cdc592888f431da0731337b8","versionType":"git"},{"lessThan":"6cb79e6499228cfdbd4b3301371ce74d01cd2f80","status":"affected","version":"15f02b91056253e8cdc592888f431da0731337b8","versionType":"git"},{"lessThan":"4ef05db5b08b176a551b4a6287372045998806b0","status":"affected","version":"15f02b91056253e8cdc592888f431da0731337b8","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["net/bluetooth/l2cap_core.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.7"},{"lessThan":"5.7","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.271","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.222","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.189","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.158","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.111","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.53","versionType":"semver"},{"lessThanOrEqual":"7.2.*","status":"unaffected","version":"7.2.7","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.3-rc2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.271","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.222","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.189","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.158","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.111","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.53","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2.7","versionStartIncluding":"5.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.3-rc2","versionStartIncluding":"5.7","vulnerable":true}],"negate":false,"operator":"OR"}]}],"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":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"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."}]}],"providerMetadata":{"dateUpdated":"2026-10-03T11:02:26.927Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"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"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-98108","datePublished":"2026-09-25T10:35:56.935Z","dateReserved":"2026-09-25T10:25:14.316Z","dateUpdated":"2026-10-03T11:02:26.927Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-09-25 11:17:41","lastModifiedDate":"2026-10-03 11:18:32","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"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","attackVector":"ADJACENT_NETWORK","attackComplexity":"HIGH","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"HIGH","availabilityImpact":"HIGH"},"exploitabilityScore":1.6,"impactScore":5.9}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"98108","Ordinal":"1","Title":"Bluetooth: L2CAP: fix chan mode for LE_CONN_REQ + EXT_FLOWCTL pc","CVE":"CVE-2026-98108","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"98108","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"Bluetooth: L2CAP: fix chan mode for LE_CONN_REQ + EXT_FLOWCTL pc"}]}}}