CVE-2026-77271

MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (bypass of CVE-2026-27825)

State: Published
Severity: 8.3 High
Published: Sep 22, 2026
Updated: Sep 24, 2026
Reserved: Aug 20, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	8.3 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N	GitHub_M

Weaknesses

CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-94 Improper Control of Generation of Code ('Code Injection')

Affected Products

Product	Versions
mcp-atlassiansooperset	< 0.22.0Affected

References

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