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CVE-2026-77246

7.4 · HIGH

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

Published Sep 22, 2026mcp-atlassianCWE-22EPSS 0.47%

Overview

CVE-2026-77246 is a high-severity vulnerability affecting mcp-atlassian mcp_atlassian. It was published on September 22, 2026 and has a CVSS 3.1 base score of 7.4 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.4, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are 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, an HTTP transport deployment with READ_ONLY_MODE=false accepts a request without an Authorization identity and permits attacker-controlled Atlassian service headers, including X-Atlassian-Confluence-Url, to select a public attacker hostname or one allowed by MCP_ALLOWED_URL_DOMAINS. A caller can then invoke confluence_upload_attachment or the Jira attachment variant in src/mcp_atlassian/jira/attachments.py with a server-local file_path and cause the MCP process to send the file to the selected attachment endpoint. 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-2026-77246?

CVE-2026-77246 is a high-severity vulnerability affecting mcp-atlassian mcp_atlassian. It was published on September 22, 2026 and has a CVSS 3.1 base score of 7.4 (HIGH).

How severe is CVE-2026-77246?

This vulnerability has a CVSS 3.1 base score of 7.4, rated HIGH. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-77246?

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-2026-77246?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-77246 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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