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CVE-2026-77266

6.5 · MEDIUM

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira).

Published Sep 22, 2026mcp-atlassianCWE-22EPSS 0.50%

Overview

CVE-2026-77266 is a medium-severity vulnerability affecting mcp-atlassian mcp_atlassian. It was published on September 22, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical description

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, upload_attachment accepts absolute paths and traversal sequences without constraining the resolved path to the server workspace. An MCP caller with attachment access can read a chosen server-local file and exfiltrate it through Jira or Confluence. The advisory traces the vulnerable input and processing flow through upload_attachment, file_path, and path traversal, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

Remediation

Check the references section for vendor advisories and patches from mcp-atlassian. Update mcp_atlassian to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected products

VendorProductVersionsStatus
mcp-atlassianmcp_atlassian>= 0, < 0.22.0Affected

Frequently asked questions

What is CVE-2026-77266?

CVE-2026-77266 is a medium-severity vulnerability affecting mcp-atlassian mcp_atlassian. It was published on September 22, 2026 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2026-77266?

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-77266?

Check the references section for vendor advisories and patches from mcp-atlassian. Update mcp_atlassian to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-77266?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-77266 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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