CVE-2026-77267

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. This issue is fixed in version 0.22.0.

• CWE-918

• https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460Patch
• https://github.com/sooperset/mcp-atlassian/pull/1448Issue Tracking, Patch
• https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0Release Notes
• https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-5wf4-jqxh-8gm3Exploit, Vendor Advisory
• https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-5wf4-jqxh-8gm3Exploit, Vendor Advisory

Published

Sep 22, 2026

Last Modified

Sep 29, 2026

Status

Analyzed

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