Vulnerability Details 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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.003
EPSS Ranking 16.1%
CVSS Severity
CVSS v3 Score 5.9
References
- 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-49xv-9743-pw8w
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-49xv-9743-pw8w
Products affected by CVE-2026-77265
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cpe:2.3:a:mcp-atlassian:mcp_atlassian:*