CVE-2026-77272
Medium
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.
SeverityMedium
CVSS5.4
Exploit probability—
ProductMcp-atlassian Mcp Atlassian
PublishedSep 22, 2026
First seenSep 22, 2026
Weakness typeCWE-79Cross-site scripting (XSS)
How to fix
Update
- mcp-atlassian mcp_atlassian0.22.0 or later
- mcp-atlassian0.22.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mcp-atlassian mcp_atlassian | v < 0.22.0 | 0.22.0 |
| mcp-atlassianPyPI | v < 0.22.0 | 0.22.0 |
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