The mcp-atlassian library is vulnerable to sensitive information exposure due to the insecure storage of authentication tokens, posing a significant risk of account compromise to local users.

This vulnerability involves the cleartext storage of sensitive authentication tokens within the local file system. A local user with low privileges can access these tokens if the host system configuration employs a permissive umask, allowing for unauthorized reuse of the associated Atlassian session.

The compromise of Atlassian access and refresh tokens enables unauthorized actors to impersonate the legitimate user within Confluence and Jira environments. Given the CVSS score of 6.1, this medium severity flaw presents a substantial risk to data confidentiality and internal system integrity by bypassing standard authentication controls.

Immediate Action: Update the mcp-atlassian package to version 0.22.0 or later to ensure tokens are handled with appropriate file permissions.

Proactive Monitoring: Audit local file system permissions for the .mcp-atlassian directory and review system logs for unauthorized access to configuration files.

Compensating Controls: Implement strict umask settings across organizational workstations and servers to restrict unauthorized read access to sensitive user directories.

Public Exploit Available: No (exploit_available: unknown)

Security teams must prioritize updating the mcp-atlassian library to the patched version 0.22.0 immediately. While this attack requires local access, the potential for persistent session hijacking necessitates prompt remediation to protect sensitive enterprise resources integrated with Atlassian products.