CVE-2026-31220
PySyft (Syft Datasite/Server) versions 0.9.5 and earlier are vulnerable to remote code execution due to insufficient validation and sandboxing of user-submitted code. The system allows low-privileged users to submit Python functions (via @sy.syft_function()) for remote execution on the server. While a code approval mechanism exists, the submitted code undergoes no security checks for dangerous operations (e.g., file access, command execution). Once approved, the code is executed within the server process using exec() and eval() functions without proper isolation. A remote attacker can leverage this to execute arbitrary Python code on the server, leading to complete compromise of the server environment.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Puntuación base: 9.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 1.20%
- Percentil entre todas las CVEs puntuadas: 67
- Fecha de la puntuación: 5/10/2026
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.
- Explotación
T1190Exploit Public-Facing Applicationinitial access95 % - Impacto principal
T1059Command and Scripting Interpreterexecution95 % - Impacto secundario
T1005Data from Local Systemcollection75 %
Vector CVSS AV:N/AC:L/PR:N permite explotación remota sin privilegios (T1190). Exec/eval() de código Python genera ejecución arbitraria (T1059). Acceso al entorno del servidor implica lectura de datos locales (T1005).
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
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-94
Referencias
JSON original (NVD)
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"id": "CVE-2026-31220",
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"id": "CVE-2026-31220",
"role": "CISA Coordinator",
"options": [
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"exploitation": "none"
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{
"automatable": "yes"
},
{
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"version": "2.0.3",
"timestamp": "2026-05-15T17:54:50.389572Z"
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"cvssMetricV31": [
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"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
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"affected": [
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"published": "2026-05-12T16:16:13.913",
"references": [
{
"url": "https://github.com/OpenMined/PySyft",
"source": "cve@mitre.org"
},
{
"url": "https://www.notion.so/CVE-2026-31220-35d1e1393188814186b9e00114a8aba7",
"source": "cve@mitre.org"
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"value": "PySyft (Syft Datasite/Server) versions 0.9.5 and earlier are vulnerable to remote code execution due to insufficient validation and sandboxing of user-submitted code. The system allows low-privileged users to submit Python functions (via @sy.syft_function()) for remote execution on the server. While a code approval mechanism exists, the submitted code undergoes no security checks for dangerous operations (e.g., file access, command execution). Once approved, the code is executed within the server process using exec() and eval() functions without proper isolation. A remote attacker can leverage this to execute arbitrary Python code on the server, leading to complete compromise of the server environment."
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],
"lastModified": "2026-06-17T10:33:27.147",
"sourceIdentifier": "cve@mitre.org"
}