MCP Atlassian is a Model Context Protocol server used with Atlassian products. In versions before 0.22.0, the _make_ssrf_safe_hook function is missing from JiraFetcher and ConfluenceFetcher sessions created via basic-auth and oauth_pat branches. This omission allows sessions to follow redirects returned by a compromised or attacker-controlled Atlassian instance to internal addresses without revalidating the destination, resulting in a Server-Side Request Forgery (CWE-918) vulnerability. The vulnerability is resolved in version 0.22.0.

An attacker who can control or compromise a configured Atlassian instance may exploit this vulnerability to cause the MCP Atlassian server to make unauthorized requests to internal network addresses. This can lead to unauthorized information disclosure (high confidentiality impact) and partial integrity loss, but does not affect availability. The CVSS 3.1 score is 7.1 (high severity) reflecting network attack vector, high complexity, low privileges required, no user interaction, and scope change.

Upgrade MCP Atlassian to version 0.22.0 or later where the vulnerability is fixed by including the _make_ssrf_safe_hook in the affected session branches. No other mitigations are specified. Patch status is confirmed fixed in version 0.22.0.