CVE-2026-43134 (GCVE-0-2026-43134)
Vulnerability from cvelistv5
Published
2026-05-06 11:27
Modified
2026-08-05 12:26
Severity ?
8.1 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix missing key size check for L2CAP_LE_CONN_REQ This adds a check for encryption key size upon receiving L2CAP_LE_CONN_REQ which is required by L2CAP/LE/CFC/BV-15-C which expects L2CAP_CR_LE_BAD_KEY_SIZE.
References
Impacted products
Vendor Product Version
Linux Linux Version: 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d
Version: 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d
Version: 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d
Version: 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d
Version: 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d
Version: 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d
Version: 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d
Version: 27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d
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{
  "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": [
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              "status": "affected",
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              "versionType": "git"
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              "versionType": "git"
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            {
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              "status": "affected",
              "version": "27e2d4c8d28be1d1b4ecfbffab572d7dbd35254d",
              "versionType": "git"
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            {
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            }
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        },
        {
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          "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": "3.14"
            },
            {
              "lessThan": "3.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.252",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.202",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.165",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.128",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.16",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.252",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.202",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "3.14",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.128",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.16",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.6",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                },
                {
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                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "3.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
            "version": "3.1"
          },
          "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\u2019s 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": {
        "dateUpdated": "2026-08-05T12:26:10.307Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "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"
        }
      ],
      "title": "Bluetooth: L2CAP: Fix missing key size check for L2CAP_LE_CONN_REQ",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43134",
    "datePublished": "2026-05-06T11:27:21.541Z",
    "dateReserved": "2026-05-01T14:12:55.988Z",
    "dateUpdated": "2026-08-05T12:26:10.307Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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