CVE-2026-53587

{
  "id": "CVE-2026-53587",
  "sourceIdentifier": "[email protected]",
  "published": "2026-08-20T19:16:55.137",
  "lastModified": "2026-10-26T10:10:00.140",
  "vulnStatus": "Awaiting Analysis",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "libgit2 is a portable C implementation of the Git core methods provided as a linkable library with a solid API, allowing to build Git functionality into your application. Prior to 1.8.6 and 1.9.5, libgit2 performs a fixed-size strncmp in set_data in src/libgit2/transports/smart_pkt.c without first verifying that the smart-protocol pkt-line capability buffer contains 14 bytes. A malicious Git server can make bytes after the pkt-line complete object-format=, causing format_str to advance beyond the pkt-line and the following memchr length calculation to underflow. The resulting heap out-of-bounds walk can crash a client during the first refs-advertisement packet over HTTP, HTTPS, SSH, or the Git protocol. This issue is fixed in versions 1.8.6 and 1.9.5."
    },
    {
      "lang": "es",
      "value": "libgit2 es una implementación portátil en C de los métodos centrales de Git proporcionada como una biblioteca enlazable con una API sólida, que permite integrar la funcionalidad de Git en su aplicación. Antes de las versiones 1.8.6 y 1.9.5, libgit2 realiza un strncmp de tamaño fijo en set_data en src/libgit2/transports/smart_pkt.c sin verificar primero que el búfer de capacidad pkt-line del protocolo inteligente contenga 14 bytes. Un servidor Git malicioso puede hacer que los bytes después de la pkt-line completen object-format=, haciendo que format_str avance más allá de la pkt-line y que el cálculo de longitud de memchr subsiguiente sufra un desbordamiento negativo. El recorrido resultante de la memoria dinámica (heap) fuera de límites puede bloquear a un cliente durante el primer paquete de anuncio de referencias a través de HTTP, HTTPS, SSH o el protocolo Git. Este problema está solucionado en las versiones 1.8.6 y 1.9.5."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "libgit2",
          "product": "libgit2",
          "versions": [
            {
              "version": "< 1.8.6",
              "status": "affected"
            },
            {
              "version": ">= 1.9.0, < 1.9.5",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-08-20T19:18:28.320266Z",
          "id": "CVE-2026-53587",
          "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-20"
        },
        {
          "lang": "en",
          "value": "CWE-125"
        },
        {
          "lang": "en",
          "value": "CWE-126"
        },
        {
          "lang": "en",
          "value": "CWE-1284"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/libgit2/libgit2/commit/2c0ce8c0132ac38ab0db28239462a671e2e5440e",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libgit2/libgit2/commit/affda60c10fcef16723451c0d7dc71b71dc20ad3",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libgit2/libgit2/commit/d7a9fb87f504434e9f45228678953c4fa56e7640",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libgit2/libgit2/releases/tag/v1.8.6",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libgit2/libgit2/releases/tag/v1.9.5",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libgit2/libgit2/security/advisories/GHSA-pm24-4jhq-3xvm",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/libgit2/libgit2/security/advisories/GHSA-pm24-4jhq-3xvm",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}