CVE-2026-77250 (GCVE-0-2026-77250)

Vulnerability from cvelistv5 – Published: 2026-09-22 17:51 – Updated: 2026-09-22 18:42
VLAI
Title
MCP Atlassian: OAuth fallback token storage writes plaintext access and refresh tokens with group-readable permissions
Summary
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.
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-22 18:42 UTC
CWE
  • CWE-312 - Cleartext Storage of Sensitive Information
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7729 records in the last 180 days details
Impacted products
Vendor Product Version CPE status
sooperset mcp-atlassian Affected: < 0.22.0
guessed Create a notification for this product.
Show details on NVD website

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