{"id":"CVE-2026-43134","state":"PUBLISHED","title":"Bluetooth: L2CAP: Fix missing key size check for L2CAP_LE_CONN_REQ","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix missing key size check for L2CAP_LE_CONN_REQ\n\nThis adds a check for encryption key size upon receiving\nL2CAP_LE_CONN_REQ which is required by L2CAP/LE/CFC/BV-15-C which\nexpects L2CAP_CR_LE_BAD_KEY_SIZE.","publishedAt":"2026-05-06T11:27:21.541Z","updatedAt":"2026-10-19T19:16:21.882Z","severity":{"score":8.1,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"335071c0c3637064ec250481f589075db44fe4e6","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"fa6ad76fa8623c0a50d529cd5726fa5d819a3be4","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"9118601ff90b79e8df3c0c98f48ae00c1b02ecef","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"481ea39b342c347b6ac029f3d418486280be4e45","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"ec91078e132179b04e0c3906b599816c056ceaad","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"96581749c7c14fbec32c35728520867929600041","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"8dd43f9a9323f9c01bc8246da8d81a4c783c9e97","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"138d7eca445ef37a0333425d269ee59900ca1104","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.14","versionType":"semver"},{"version":"5.10.252","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.202","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.165","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.128","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.16","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.6","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","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"]}],"references":["https://git.kernel.org/stable/c/335071c0c3637064ec250481f589075db44fe4e6","https://git.kernel.org/stable/c/fa6ad76fa8623c0a50d529cd5726fa5d819a3be4","https://git.kernel.org/stable/c/9118601ff90b79e8df3c0c98f48ae00c1b02ecef","https://git.kernel.org/stable/c/481ea39b342c347b6ac029f3d418486280be4e45","https://git.kernel.org/stable/c/ec91078e132179b04e0c3906b599816c056ceaad","https://git.kernel.org/stable/c/96581749c7c14fbec32c35728520867929600041","https://git.kernel.org/stable/c/8dd43f9a9323f9c01bc8246da8d81a4c783c9e97","https://git.kernel.org/stable/c/138d7eca445ef37a0333425d269ee59900ca1104"],"weaknesses":["CWE-326"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/43xxx/CVE-2026-43134.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-43134","state":"PUBLISHED","datePublished":"2026-05-06T11:27:21.541Z","dateUpdated":"2026-10-19T19:16:21.882Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-05-01T14:12:55.988Z"},"containers":{"cna":{"title":"Bluetooth: L2CAP: Fix missing key size check for L2CAP_LE_CONN_REQ","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix missing key size check for L2CAP_LE_CONN_REQ\n\nThis adds a check for encryption key size upon receiving\nL2CAP_LE_CONN_REQ which is required by L2CAP/LE/CFC/BV-15-C which\nexpects L2CAP_CR_LE_BAD_KEY_SIZE."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"335071c0c3637064ec250481f589075db44fe4e6","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"fa6ad76fa8623c0a50d529cd5726fa5d819a3be4","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"9118601ff90b79e8df3c0c98f48ae00c1b02ecef","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"481ea39b342c347b6ac029f3d418486280be4e45","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"ec91078e132179b04e0c3906b599816c056ceaad","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"96581749c7c14fbec32c35728520867929600041","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"8dd43f9a9323f9c01bc8246da8d81a4c783c9e97","versionType":"git"},{"version":"27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d","status":"affected","lessThan":"138d7eca445ef37a0333425d269ee59900ca1104","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/bluetooth/l2cap_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.14","versionType":"semver"},{"version":"5.10.252","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.202","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.165","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.128","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.75","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.16","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.6","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","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"]}],"references":[{"url":"https://git.kernel.org/stable/c/335071c0c3637064ec250481f589075db44fe4e6"},{"url":"https://git.kernel.org/stable/c/fa6ad76fa8623c0a50d529cd5726fa5d819a3be4"},{"url":"https://git.kernel.org/stable/c/9118601ff90b79e8df3c0c98f48ae00c1b02ecef"},{"url":"https://git.kernel.org/stable/c/481ea39b342c347b6ac029f3d418486280be4e45"},{"url":"https://git.kernel.org/stable/c/ec91078e132179b04e0c3906b599816c056ceaad"},{"url":"https://git.kernel.org/stable/c/96581749c7c14fbec32c35728520867929600041"},{"url":"https://git.kernel.org/stable/c/8dd43f9a9323f9c01bc8246da8d81a4c783c9e97"},{"url":"https://git.kernel.org/stable/c/138d7eca445ef37a0333425d269ee59900ca1104"}],"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:N","baseScore":8.1,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:A - The vulnerable request is an incoming Bluetooth LE L2CAP signaling packet from a nearby Bluetooth peer, so exploitation requires adjacent radio proximity rather than IP network or local shell access.\nAC:L - An attacker who can establish an LE link can send an L2CAP_LE_CONN_REQ with an insufficient encryption key size and reliably reach the missing check; there is no race or condition outside attacker control.\nPR:N - The attacker does not need privileges on the target system; Bluetooth pairing/encryption is a protocol precondition, not an OS privilege, and the vulnerable authorization decision is made from received peer traffic.\nUI:N - In a reasonable deployment with a listening LE L2CAP service and connectable device, exploitation is triggered by the adjacent peer’s protocol messages without requiring the victim to open a file, mount anything, or perform an action.\nS:U - The issue bypasses Bluetooth/L2CAP security policy within the same kernel and host Bluetooth service security authority, with no VM, sandbox, or hardware boundary escape.\nC:H - Accepting a channel despite an insufficient encryption key can expose all data carried by a protected LE Credit Based L2CAP service; for high-impact Bluetooth deployments, that can disclose sensitive application or device-control data.\nI:H - The same security bypass can allow an adjacent peer using inadequate encryption strength to send commands or modify state over a service that should have rejected the connection, giving high integrity impact in the protected service context.\nA:N - The bug is a missing key-size enforcement check and does not indicate memory corruption, panic, deadlock, resource exhaustion, or another availability failure."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-05T12:26:10.307Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"5.10.252"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"5.15.202"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"6.1.165"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"6.6.128"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"6.12.75"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"6.18.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"6.19.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.14","versionEndExcluding":"7.0"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-43134","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:15:03.252855Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-326","lang":"en","type":"CWE","description":"CWE-326 Inadequate Encryption Strength"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T19:16:21.882Z"}}]}}}