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.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Mcp-Atlassian Mcp_Atlassian
cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:*
|
— |
0.22.0
|
References 4
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c2…
security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/pull/1448
security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0
security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v…
security-advisories@github.com