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CVE-2026-77250

Estado: AnalizadaMedia (6.1)—

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, OAuthConfig writes a plaintext fallback file containing access and refresh tokens under the user's .mcp-atlassian directory using process-default permissions. On systems with a permissive umask, same-group or other local users and processes can read the persisted tokens and reuse the associated Atlassian access. The advisory traces the vulnerable input and processing flow through OAuthConfig._save_tokens, ~/.mcp-atlassian/oauth-<client_id>.json, access_token, and refresh_token, 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.

AV:L con PR:L indica explotación local con privilegios (T1068). CWE-312 revela escritura en permisos inseguros; otro usuario lee tokens OAuth en ~/.mcp-atlassian/ (T1552.001: credenciales no protegidas). Los tokens reutilizables permiten suplantación de cuenta (T1078.001).

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

Password PoliciesUser TrainingThreat Intelligence ProgramRestrict File and Directory PermissionsMulti-factor AuthenticationExecution Prevention

Tecnologías afectadas (1)

Mcp-atlassian — MCP Atlassian

CWE

Referencias

JSON original (NVD)

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