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CVE-2026-76875

Estado: Pendiente de análisisMedia (6.3)—

PyPy before versions 3.11.16 and 3.12.14 contains a use-after-free vulnerability in the pyexpat module's ExternalEntityParserCreate function that allows attackers to corrupt memory by supplying a crafted XML document to applications that create external-entity sub-parsers without retaining a reference to the parent parser. The child parser retains a raw C back-pointer to the parent parser struct while PyPy's tracing garbage collector can free the parent's C struct, causing bundled libexpat to dereference the freed pointer on every parsed token, producing memory corruption.

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.

Use-after-free en módulo pyexpat de PyPy explotable remotamente via XML malformado, causando corrupción de memoria (CWE-416) que lleva a denegación de servicio o corrupción de datos.

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

Filter Network TrafficVulnerability ScanningRestrict File and Directory PermissionsPrivileged Account ManagementRemote Data StorageNetwork Segmentation

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Pypy — PypyAI

CWE

Referencias

JSON original (NVD)

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  "id": "CVE-2026-76875",
  "cveTags": [],
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          "id": "CVE-2026-76875",
          "role": "CISA Coordinator",
          "options": [
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              "exploitation": "none"
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              "automatable": "yes"
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            {
              "technicalImpact": "partial"
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          "version": "2.0.3",
          "timestamp": "2026-10-02T12:07:14.237053Z"
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    "cvssMetricV31": [
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          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "NONE",
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          "Automatable": "NOT_DEFINED",
          "attackVector": "NETWORK",
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          "valueDensity": "NOT_DEFINED",
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          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
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          "vulnAvailabilityImpact": "NONE",
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          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "subConfidentialityImpact": "NONE",
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          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
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  "affected": [
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      "affectedData": [
        {
          "repo": "https://github.com/pypy/pypy",
          "vendor": "PyPy",
          "product": "PyPy",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "3.11.16",
              "versionType": "semver"
            },
            {
              "status": "affected",
              "version": "3.12.0",
              "lessThan": "3.12.14",
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  "published": "2026-09-29T13:17:52.280",
  "references": [
    {
      "url": "https://doc.pypy.org/release-v8.0.0.html",
      "source": "disclosure@vulncheck.com"
    },
    {
      "url": "https://github.com/pypy/pypy/releases/tag/release-pypy3.11-v8.0.0",
      "source": "disclosure@vulncheck.com"
    },
    {
      "url": "https://github.com/pypy/pypy/releases/tag/release-pypy3.12-v8.0.0",
      "source": "disclosure@vulncheck.com"
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      "description": [
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          "value": "CWE-416"
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  "descriptions": [
    {
      "lang": "en",
      "value": "PyPy before versions 3.11.16 and 3.12.14 contains a use-after-free vulnerability in the pyexpat module's ExternalEntityParserCreate function that allows attackers to corrupt memory by supplying a crafted XML document to applications that create external-entity sub-parsers without retaining a reference to the parent parser. The child parser retains a raw C back-pointer to the parent parser struct while PyPy's tracing garbage collector can free the parent's C struct, causing bundled libexpat to dereference the freed pointer on every parsed token, producing memory corruption."
    }
  ],
  "lastModified": "2026-10-02T13:17:55.747",
  "sourceIdentifier": "disclosure@vulncheck.com"
}