CVE-2026-77272
MEDIUMCVSS 5.4Description
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.
Timeline
Published:September 22nd, 2026 7:16 PM
Last modified:September 28th, 2026 1:10 PM
CVSS Scoring
CVSS v3: 5.4 (MEDIUM)
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Affected Software
From NVD CPE configuration data
Vendors
mcp-atlassian
Products
mcp_atlassian
Weaknesses (CWE)
References & Reports
Advisories, patches, and third-party reports
- https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460Patch
- https://github.com/sooperset/mcp-atlassian/pull/1448Issue Tracking
- https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0Release Notes
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g2r2-3j32-j27xExploit
Source: NIST NVD · Data may lag official sources by up to one minute