CVE-2026-33023

{
  "id": "CVE-2026-33023",
  "cveTags": [],
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          "id": "CVE-2026-33023",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-04-15T18:48:25.027963Z"
        }
      }
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    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
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        "impactScore": 5.9,
        "exploitabilityScore": 1.8
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  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "saitoha",
          "product": "libsixel",
          "versions": [
            {
              "status": "affected",
              "version": "< 1.8.7-r1"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-04-14T23:16:27.820",
  "references": [
    {
      "url": "https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1",
      "tags": [
        "Release Notes"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/saitoha/libsixel/security/advisories/GHSA-hr25-g2j6-qjw6",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/saitoha/libsixel/security/advisories/GHSA-hr25-g2j6-qjw6",
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        "Vendor Advisory"
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  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. In versions 1.8.7 and prior, when built with the --with-gdk-pixbuf2 option, a use-after-free vulnerability exists in load_with_gdkpixbuf() in loader.c. The cleanup path manually frees the sixel_frame_t object and its internal buffers without consulting the reference count, even though the object was created via the refcounted constructor sixel_frame_new() and exposed to the public callback. A callback that calls sixel_frame_ref(frame) to retain a logically valid reference will hold a dangling pointer after sixel_helper_load_image_file() returns, and any subsequent access to the frame or its fields triggers a use-after-free confirmed by AddressSanitizer. The root cause is a consistency failure between two cleanup strategies in the same codebase: sixel_frame_unref() is used in load_with_builtin() but raw free() is used in load_with_gdkpixbuf(). An attacker supplying a crafted image to any application built against libsixel with gdk-pixbuf2 support can trigger this reliably, potentially leading to information disclosure, memory corruption, or code execution. This issue has been fixed in version 1.8.7-r1."
    },
    {
      "lang": "es",
      "value": "libsixel es una implementación de codificador/decodificador SIXEL derivada del sixel de kmiya. En las versiones 1.8.7 y anteriores, cuando se compila con la opción --with-gdk-pixbuf2, existe una vulnerabilidad de uso después de liberación en load_with_gdkpixbuf() en loader.c. La ruta de limpieza libera manualmente el objeto sixel_frame_t y sus búferes internos sin consultar el recuento de referencias, a pesar de que el objeto fue creado a través del constructor con recuento de referencias sixel_frame_new() y expuesto a la devolución de llamada pública. Una devolución de llamada que llama a sixel_frame_ref(frame) para retener una referencia lógicamente válida mantendrá un puntero colgante después de que sixel_helper_load_image_file() regrese, y cualquier acceso posterior al marco o sus campos activa un uso después de liberación confirmado por AddressSanitizer. La causa raíz es una falla de consistencia entre dos estrategias de limpieza en la misma base de código: sixel_frame_unref() se usa en load_with_builtin() pero free() sin procesar se usa en load_with_gdkpixbuf(). Un atacante que suministre una imagen manipulada a cualquier aplicación compilada contra libsixel con soporte para gdk-pixbuf2 puede activar esto de manera fiable, lo que podría conducir a revelación de información, corrupción de memoria o ejecución de código. Este problema ha sido solucionado en la versión 1.8.7-r1."
    }
  ],
  "lastModified": "2026-07-25T11:10:00.100",
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