CVE-2026-77252
Received Received - Intake

Authentication Bypass in MCP Atlassian Server

Publication date: 2026-09-22

Last updated on: 2026-09-22

Assigner: GitHub, Inc.

Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, caller-supplied projects_filter and spaces_filter arguments can replace administrator-configured allowlists, and caller-provided project or space clauses can suppress the configured restriction. A caller can search projects or spaces outside the intended boundary when the configured Atlassian credentials can access them. The advisory traces the vulnerable input and processing flow through JIRA_PROJECTS_FILTER, CONFLUENCE_SPACES_FILTER, projects_filter, spaces_filter, SearchMixin.search_issues, and SearchMixin.search, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

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Meta Information

Published
2026-09-22
Last Modified
2026-09-22
Generated
2026-09-22
AI Q&A
2026-09-22
EPSS Evaluated
N/A
NVD
CVE-2026-77252
EUVD
EUVD-2026-84623

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
atlassian mcp to 0.22.0 (exc)
atlassian confluence *
atlassian jira *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-284 The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Attack-Flow Graph

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Executive Summary

CVE-2026-77252 is a vulnerability in MCP Atlassian versions prior to 0.22.0. It allows bypassing administrator-configured allowlists for project and space searches in Jira and Confluence. Attackers can override filters or include specific clauses like 'project =' or 'space =' to access restricted projects or spaces within the configured Atlassian account's access.

Detection Guidance

Check the installed version of mcp-atlassian. If it is below 0.22.0, the system is vulnerable. Run: pip show mcp-atlassian or grep version in package files.

Impact Analysis

This vulnerability may allow unauthorized users to search and access projects or spaces they are not permitted to view, even if those resources are restricted by configured allowlists. However, access is limited to what the configured Atlassian credentials can reach.

Mitigation Strategies

Upgrade mcp-atlassian to version 0.22.0 or later immediately. Review search queries for unauthorized project or space clauses like project =, project in, or space =.

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