CVE-2026-77271

What it is

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.

At a glance

Exploitability

Can be exploited over the network with a low-privilege account. High risk of data exposure.

Exploit odds

0.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-22 18:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-09-28 13:45 UTC Last updatedMost recent change to the record

Details

Published

2026-09-22 18:17 UTC

Last modified

2026-09-28 13:45 UTC

Exploit probability

0.6% · EPSS, next 30 days

Weakness

CWE-22 · Path traversal

Record status

Analyzed

Affected

• mcp-atlassian Mcp Atlassian < 0.22.0

Attack profile CVSS 4.0 · 8.3

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

Low

User interaction

None

Confidentiality

High

Integrity

None

Availability

None