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CVE PROGRAM SOURCE RECORD5.4 Medium

CVE-2026-77272

MCP Atlassian: Reflected XSS in OAuth Setup Callback Handler

Description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the OAuth error query parameter is passed to CallbackHandler._send_response in oauth_setup.py and interpolated into an HTML page without escaping. A crafted authorization callback can inject markup or script that executes in the browser of a user completing the OAuth flow. This issue is fixed in version 0.22.0.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

sooperset mcp-atlassian

  • < 0.22.0affected

References