CVE-2026-77250
Severity CVSS v4.0:
Pending analysis
Type:
CWE-312
Cleartext Storage of Sensitive Information
Publication date:
22/09/2026
Last modified:
23/09/2026
Description
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-.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.
Impact
Base Score 3.x
6.10
Severity 3.x
MEDIUM
References to Advisories, Solutions, and Tools
- https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
- https://github.com/sooperset/mcp-atlassian/pull/1448
- https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6