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CVE-2026-77242

Estado: AnalizadaAlta (7.5)—

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, validate_url_for_ssrf checks a hostname's resolved addresses, but Requests and urllib3 resolve the hostname again when connecting. A caller can use a short-lived DNS answer that is public during validation and private during connection, preserving unauthenticated access to internal or metadata endpoints despite the earlier CVE-2026-27826 remediation. The advisory traces the vulnerable input and processing flow through validate_url_for_ssrf, _check_dns_resolution, socket.getaddrinfo, and _make_ssrf_safe_hook, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

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.

SSRF por race condition DNS: AV:N sin autenticación permite bypassear validación de URL contra endpoints internos/metadata. CWE-918 confirma SSRF; CWE-367 indica TOCTOU.

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 ScanningSSL/TLS InspectionPrivileged Account ManagementNetwork SegmentationNetwork Intrusion Prevention

Tecnologías afectadas (1)

Mcp-atlassian — MCP Atlassian

CWE

Referencias

JSON original (NVD)

Mostrar
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  "id": "CVE-2026-77242",
  "cveTags": [],
  "metrics": {
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          "options": [
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          "version": "2.0.3",
          "timestamp": "2026-09-22T18:48:54.750780Z"
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          "integrityImpact": "LOW",
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          "attackComplexity": "HIGH",
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          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
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  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "source": "security-advisories@github.com",
      "description": [
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    {
      "lang": "en",
      "value": "MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, validate_url_for_ssrf checks a hostname's resolved addresses, but Requests and urllib3 resolve the hostname again when connecting. A caller can use a short-lived DNS answer that is public during validation and private during connection, preserving unauthenticated access to internal or metadata endpoints despite the earlier CVE-2026-27826 remediation. The advisory traces the vulnerable input and processing flow through validate_url_for_ssrf, _check_dns_resolution, socket.getaddrinfo, and _make_ssrf_safe_hook, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0."
    }
  ],
  "lastModified": "2026-09-29T15:41:42.950",
  "configurations": [
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