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[ CVE-2026-77271 · Published 22 Sep 2026 ]

MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (bypass of GHSA-xjgw-4wvw-rgm4)

CVSS 8.3 EPSS <1%Fix available

[ Why it matters ]Priority signals

  • Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, validate_safe_path defaults its base directory to os.getcwd(), and affected Confluence attachment call sites omit base_dir, allowing attacker-selected writes within the working directory. This Python module overwrite can provide code execution when the application later imports the modified module, bypassing the remediation tracked as CVE-2026-27825. This issue is fixed in version 0.22.0.

[ Fixes ]Fixes and patches

  • mcp-atlassian 0.22.0Fixed version · GitHub Advisories · pip package mcp-atlassian: upgrade to 0.22.0 or later (affected < 0.22.0)

[ Packages ]Affected open-source packages

[ References ]References