CVE-2026-77265

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, header-supplied Jira or Confluence URLs are resolved and validated before the HTTP client resolves the hostname again for the connection. An unauthenticated caller can use a DNS-rebinding hostname that returns a public address during validation and an internal address during connection, causing requests to internal or metadata services. The advisory traces the vulnerable input and processing flow through X-Atlassian-Jira-Url, X-Atlassian-Confluence-Url, validate_url_for_ssrf, and DNS rebinding, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

• https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460Patch
• https://github.com/sooperset/mcp-atlassian/pull/1448Issue Tracking
• https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0Release Notes
• https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-49xv-9743-pw8wExploit
• https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-49xv-9743-pw8wExploit