CVE-2026-63383

{
  "id": "CVE-2026-63383",
  "sourceIdentifier": "[email protected]",
  "published": "2026-08-20T18:16:35.917",
  "lastModified": "2026-10-26T10:10:00.140",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c when decode_tag_internal requests at most five bytes from evbuffer_pullup but iterates using the full logical buffer length. A fragmented evbuffer containing a six-byte malformed tag can therefore advance past the pullup window and trigger an out-of-bounds read, which can crash a process that decodes attacker-controlled tagged RPC data. This issue is fixed in versions 2.1.13 and 2.2.2-alpha."
    },
    {
      "lang": "es",
      "value": "Libevent es una biblioteca de notificación de eventos. Antes de 2.1.13 y 2.2.2-alpha, libevent puede leer más allá de una región contigua de evbuffer en event_tagging.c cuando decode_tag_internal solicita como máximo cinco bytes de evbuffer_pullup pero itera usando la longitud completa del búfer lógico. Un evbuffer fragmentado que contiene una etiqueta malformada de seis bytes puede, por lo tanto, avanzar más allá de la ventana de pullup y desencadenar una lectura fuera de límites, lo que puede bloquear un proceso que decodifica datos RPC etiquetados controlados por el atacante. Este problema está solucionado en las versiones 2.1.13 y 2.2.2-alpha."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "libevent",
          "product": "libevent",
          "versions": [
            {
              "version": ">= 2.2.0-alpha, < 2.2.2-alpha",
              "status": "affected"
            },
            {
              "version": "< 2.1.13",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "baseScore": 8.7,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnAvailabilityImpact": "HIGH",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-08-20T18:37:55.514994Z",
          "id": "CVE-2026-63383",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-125"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/libevent/libevent/commit/91ed8745eebabdd27592a83d350338a8c4626321",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libevent/libevent/commit/e1f9e21887c6b104e206a718385ba3ffc75180cb",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libevent/libevent/releases/tag/release-2.1.13-stable",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libevent/libevent/releases/tag/release-2.2.2-alpha",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libevent/libevent/security/advisories/GHSA-fj29-64w6-73h6",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libevent/libevent/security/advisories/GHSA-fj29-64w6-73h6",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}