CVE-2026-77271: mcp atlassian Path Traversal

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.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0053

Probability of exploitation

0.44%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-22 Path Traversal

CWE-94 CWE-94

Affected Products

Vendor	Product	Versions
mcp-atlassian	mcp_atlassian	< 0.22.0

References

Advisories & Patches

https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 https://github.com/sooperset/mcp-atlassian/pull/1448 https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6vmq-24h2-pj7j https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6vmq-24h2-pj7j

Exploits

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6vmq-24h2-pj7j https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6vmq-24h2-pj7j

Other References

https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0

Frequently Asked Questions

What is CVE-2026-77271? +

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. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2026-77271? +

CVE-2026-77271 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0053, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-77271? +

CVE-2026-77271 affects products from mcp-atlassian, specifically: mcp_atlassian. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-77271? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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