What is CVE-2026-77270?

CVE-2026-77270 is a medium-severity vulnerability in Sooperset Mcp-Atlassian, classified under Path Traversal. CVSS score: 6.5/10. Published 2026-09-22.

How severe is CVE-2026-77270?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Path Traversal in Sooperset Mcp-Atlassian

CVE-2026-77270

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the Jira and Confluence attachment upload tools treat caller-controlled file_path values as trusted server-local paths. The server opens the selected file and uploads it to an Atlassian issue or page, allowing an MCP caller with upload access to disclose any file readable by the server process. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, jira_upload_attachment, file_path, and open(file_path, "rb"), which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

Vulnerability class: Path Traversal (Directory Traversal)

Published 2026-09-22 · last modified 2026-09-22.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Sooperset Mcp-Atlassian — versions < 0.22.0

Weakness classification (CWE)

CWE-22 — Path Traversal

References

Frequently asked questions

What is CVE-2026-77270?: CVE-2026-77270 is a medium-severity vulnerability in Sooperset Mcp-Atlassian, classified under Path Traversal. CVSS score: 6.5/10. Published 2026-09-22.
How severe is CVE-2026-77270?: Medium severity. CVSS v3 base score is 6.5 out of 10.