FKIE_CVE-2026-31513

Vulnerability from fkie_nvd - Published: 2026-04-22 14:16 - Updated: 2026-06-17 10:33
Severity
8.1 (High) - CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req Syzbot reported a KASAN stack-out-of-bounds read in l2cap_build_cmd() that is triggered by a malformed Enhanced Credit Based Connection Request. The vulnerability stems from l2cap_ecred_conn_req(). The function allocates a local stack buffer (`pdu`) designed to hold a maximum of 5 Source Channel IDs (SCIDs), totaling 18 bytes. When an attacker sends a request with more than 5 SCIDs, the function calculates `rsp_len` based on this unvalidated `cmd_len` before checking if the number of SCIDs exceeds L2CAP_ECRED_MAX_CID. If the SCID count is too high, the function correctly jumps to the `response` label to reject the packet, but `rsp_len` retains the attacker's oversized value. Consequently, l2cap_send_cmd() is instructed to read past the end of the 18-byte `pdu` buffer, triggering a KASAN panic. Fix this by moving the assignment of `rsp_len` to after the `num_scid` boundary check. If the packet is rejected, `rsp_len` will safely remain 0, and the error response will only read the 8-byte base header from the stack.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5b35f8211a913cfe7ab9d54fa36a272d2059a588Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9d87cb22195b2c67405f5485d525190747ad5493Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a3d9c50d69785ae02e153f000da1b5fd6dbfdf1bPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7ccPatch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "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": "c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc",
              "status": "affected",
              "version": "935f324e4b2461df2cf7f02b4195082b4304c708",
              "versionType": "git"
            },
            {
              "lessThan": "5b35f8211a913cfe7ab9d54fa36a272d2059a588",
              "status": "affected",
              "version": "e981a9392800ce2c5bca196a6ab2c55e9370efaa",
              "versionType": "git"
            },
            {
              "lessThan": "a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b",
              "status": "affected",
              "version": "f3fdf2e7276a3edc5df55454275da20eac186970",
              "versionType": "git"
            },
            {
              "lessThan": "9d87cb22195b2c67405f5485d525190747ad5493",
              "status": "affected",
              "version": "c28d2bff70444a85b3b86aaf241ece9408c7858c",
              "versionType": "git"
            }
          ]
        },
        {
          "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": "6.12.80",
              "status": "affected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThan": "6.18.21",
              "status": "affected",
              "version": "6.18.16",
              "versionType": "semver"
            },
            {
              "lessThan": "6.19.11",
              "status": "affected",
              "version": "6.19.6",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "E823EB64-1F92-40BB-891C-D94D00EDA086",
              "versionEndExcluding": "6.12.80",
              "versionStartIncluding": "6.12.75",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "6C57E63A-04BA-47E0-A942-789F7236A636",
              "versionEndExcluding": "6.18.21",
              "versionStartIncluding": "6.18.16",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "1BFE33C3-C605-4CC2-9F15-3494BA78E2C9",
              "versionEndExcluding": "6.19.11",
              "versionStartIncluding": "6.19.6",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix stack-out-of-bounds read in l2cap_ecred_conn_req\n\nSyzbot reported a KASAN stack-out-of-bounds read in l2cap_build_cmd()\nthat is triggered by a malformed Enhanced Credit Based Connection Request.\n\nThe vulnerability stems from l2cap_ecred_conn_req(). The function allocates\na local stack buffer (`pdu`) designed to hold a maximum of 5 Source Channel\nIDs (SCIDs), totaling 18 bytes. When an attacker sends a request with more\nthan 5 SCIDs, the function calculates `rsp_len` based on this unvalidated\n`cmd_len` before checking if the number of SCIDs exceeds\nL2CAP_ECRED_MAX_CID.\n\nIf the SCID count is too high, the function correctly jumps to the\n`response` label to reject the packet, but `rsp_len` retains the\nattacker\u0027s oversized value. Consequently, l2cap_send_cmd() is instructed\nto read past the end of the 18-byte `pdu` buffer, triggering a\nKASAN panic.\n\nFix this by moving the assignment of `rsp_len` to after the `num_scid`\nboundary check. If the packet is rejected, `rsp_len` will safely\nremain 0, and the error response will only read the 8-byte base header\nfrom the stack."
    }
  ],
  "id": "CVE-2026-31513",
  "lastModified": "2026-06-17T10:33:53.437",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "ADJACENT_NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.2,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-04-22T14:16:50.673",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/5b35f8211a913cfe7ab9d54fa36a272d2059a588"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/9d87cb22195b2c67405f5485d525190747ad5493"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/a3d9c50d69785ae02e153f000da1b5fd6dbfdf1b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/c8e1a27edb8b4e5afb56b384acd7b6c2dec1b7cc"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}



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