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CVE-2026-31393

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Validate L2CAP_INFO_RSP payload length before access l2cap_information_rsp() checks that cmd_len covers the fixed l2cap_info_rsp header (type + result, 4 bytes) but then reads rsp->data without verifying that the payload is present: - L2CAP_IT_FEAT_MASK calls get_unaligned_le32(rsp->data), which reads 4 bytes past the header (needs cmd_len >= 8). - L2CAP_IT_FIXED_CHAN reads rsp->data[0], 1 byte past the header (needs cmd_len >= 5). A truncated L2CAP_INFO_RSP with result == L2CAP_IR_SUCCESS triggers an out-of-bounds read of adjacent skb data. Guard each data access with the required payload length check. If the payload is too short, skip the read and let the state machine complete with safe defaults (feat_mask and remote_fixed_chan remain zero from kzalloc), so the info timer cleanup and l2cap_conn_start() still run and the connection is not stalled.

Severity
HIGH
CVSS score
8.1 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-04-03 16:16:37.420000
Last modified
2026-10-19 19:17:51.010000
View original CVE JSON 
{
  "id": "CVE-2026-31393",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-04-03T16:16:37.420",
  "lastModified": "2026-10-19T19:17:51.010",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Validate L2CAP_INFO_RSP payload length before access\n\nl2cap_information_rsp() checks that cmd_len covers the fixed\nl2cap_info_rsp header (type + result, 4 bytes) but then reads\nrsp->data without verifying that the payload is present:\n\n - L2CAP_IT_FEAT_MASK calls get_unaligned_le32(rsp->data), which reads\n   4 bytes past the header (needs cmd_len >= 8).\n\n - L2CAP_IT_FIXED_CHAN reads rsp->data[0], 1 byte past the header\n   (needs cmd_len >= 5).\n\nA truncated L2CAP_INFO_RSP with result == L2CAP_IR_SUCCESS triggers an\nout-of-bounds read of adjacent skb data.\n\nGuard each data access with the required payload length check.  If the\npayload is too short, skip the read and let the state machine complete\nwith safe defaults (feat_mask and remote_fixed_chan remain zero from\nkzalloc), so the info timer cleanup and l2cap_conn_start() still run\nand the connection is not stalled."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nBluetooth: L2CAP: Validar la longitud de la carga útil de L2CAP_INFO_RSP antes del acceso\n\nl2cap_information_rsp() comprueba que cmd_len cubre la cabecera fija de l2cap_info_rsp (tipo + resultado, 4 bytes) pero luego lee rsp -> data sin verificar que la carga útil esté presente:\n\n - L2CAP_IT_FEAT_MASK llama a get_unaligned_le32(rsp -> data), que lee 4 bytes después de la cabecera (necesita cmd_len >= 8).\n\n - L2CAP_IT_FIXED_CHAN lee rsp -> data[0], 1 byte después de la cabecera (necesita cmd_len >= 5).\n\nUn L2CAP_INFO_RSP truncado con result == L2CAP_IR_SUCCESS desencadena una lectura fuera de límites de datos skb adyacentes.\n\nProteger cada acceso a datos con la comprobación de longitud de carga útil requerida. Si la carga útil es demasiado corta, omitir la lectura y permitir que la máquina de estados se complete con valores predeterminados seguros (feat_mask y remote_fixed_chan permanecen en cero desde kzalloc), para que la limpieza del temporizador de información y l2cap_conn_start() sigan ejecutándose y la conexión no se estanque."
    }
  ],
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      "affectedData": [
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          "product": "Linux",
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              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
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    }
  ],
  "metrics": {
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        "cvssData": {
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          "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "attackVector": "ADJACENT_NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 2.8,
        "impactScore": 5.2
      }
    ],
    "ssvcV203": [
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-16T15:08:44.591333Z",
          "id": "CVE-2026-31393",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
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              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
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        }
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  ],
  "configurations": [
    {
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          "operator": "OR",
          "negate": false,
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