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CVE-2026-8829

Estado: ModificadaAlta (7.5)—

HTML::Entities versions before 3.84 for Perl read freed heap memory in _decode_entities.

The XS routine backing HTML::Entities::_decode_entities cached a pointer (repl) into the entity-value SV returned by hv_fetch on the entity2char hash. When the input SV was identical to a value SV in that hash, and that value contained its own key as an entity reference, a later call to grow_gap() reallocated the SV's PV buffer and freed the backing allocation that repl still pointed into. The subsequent copy loop read repl_len bytes from the freed allocation.

The read may disclose adjacent heap contents into the destination SV.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Vulnerabilidad de lectura de memoria en librería Perl (AV:N, sin autenticación). CWE-416 (use-after-free) permite lectura de heap adyacente, revelando información sensible en memoria.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability ScanningPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over NetworkFilter Network TrafficApplication Isolation and Sandboxing

Tecnologías afectadas (1)

Oalders — Html\

CWE

Referencias

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{
  "id": "CVE-2026-8829",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-8829",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-06-04T12:59:04.771815Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.5,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 3.9
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  "affected": [
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      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "affectedData": [
        {
          "repo": "https://github.com/libwww-perl/HTML-Parser",
          "vendor": "OALDERS",
          "product": "HTML::Entities",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "3.84",
              "versionType": "custom"
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          ],
          "packageName": "HTML-Parser",
          "programFiles": [
            "util.c"
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          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "programRoutines": [
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              "name": "HTML::Entities::_decode_entities"
            }
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  "published": "2026-06-04T03:16:20.260",
  "references": [
    {
      "url": "https://github.com/libwww-perl/HTML-Parser/commit/6922552b0778c90a9587a3894e248be4d3a25e1c.patch",
      "tags": [
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      "url": "https://github.com/libwww-perl/HTML-Parser/pull/56",
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        "Patch"
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    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2026/06/04/2",
      "tags": [
        "Mailing List",
        "Third Party Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://lists.debian.org/debian-lts-announce/2026/06/msg00044.html",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "HTML::Entities versions before 3.84 for Perl read freed heap memory in _decode_entities.\n\nThe XS routine backing HTML::Entities::_decode_entities cached a pointer (repl) into the entity-value SV returned by hv_fetch on the entity2char hash. When the input SV was identical to a value SV in that hash, and that value contained its own key as an entity reference, a later call to grow_gap() reallocated the SV's PV buffer and freed the backing allocation that repl still pointed into. The subsequent copy loop read repl_len bytes from the freed allocation.\n\nThe read may disclose adjacent heap contents into the destination SV."
    },
    {
      "lang": "es",
      "value": "Las versiones de HTML::Entities anteriores a la 3.84 para Perl leían memoria de montón liberada en _decode_entities.\n\nLa rutina XS que respalda HTML::Entities::_decode_entities almacenaba en caché un puntero (repl) hacia el SV de valor de entidad devuelto por hv_fetch en el hash entity2char. Cuando el SV de entrada era idéntico a un SV de valor en ese hash, y ese valor contenía su propia clave como referencia de entidad, una llamada posterior a grow_gap() reasignaba el búfer PV del SV y liberaba la asignación de respaldo a la que repl aún apuntaba. El bucle de copia subsiguiente leía repl_len bytes de la asignación liberada.\n\nLa lectura puede divulgar contenido adyacente del montón en el SV de destino."
    }
  ],
  "lastModified": "2026-07-22T20:10:00.127",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:oalders:html\\:\\:entities:*:*:*:*:*:perl:*:*",
              "vulnerable": true,
              "matchCriteriaId": "0DB42006-30BD-4085-8C4B-F9D75404315C",
              "versionEndExcluding": "3.84"
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          "operator": "OR"
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      ]
    }
  ],
  "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
}