Vulnerability Details CVE-2026-77274
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, validate_url_for_ssrf has a backslash authority confusion because it interprets the authority differently from the Requests connection layer in the header-based Jira and Confluence URL authentication flow. A crafted URL can validate as an external hostname while the HTTP client connects to an internal host, permitting server-side requests to protected network resources. This issue is fixed in version 0.22.0.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.005
EPSS Ranking 38.0%
CVSS Severity
CVSS v3 Score 8.2
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-hgcf-4mq8-5266
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-hgcf-4mq8-5266
Products affected by CVE-2026-77274
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cpe:2.3:a:mcp-atlassian:mcp_atlassian:*