CVE-2026-73497
Received Received - Intake

SSRF via DNS Rebinding in MCP Atlassian

Publication date: 2026-09-14

Last updated on: 2026-09-14

Assigner: GitHub, Inc.

Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). From 0.17.0 until 0.22.0, validate_url_for_ssrf resolves the attacker-controlled X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url header host once at middleware time, but the outbound request is built with the raw hostname and resolves it again at connection time with no IP pinning. An attacker-controlled DNS-rebinding name can return a public IP during validation and 169.254.169.254 or another internal IP during connection, enabling unauthenticated server-side requests to cloud metadata or internal services. The flaw spans src/mcp_atlassian/utils/urls.py, src/mcp_atlassian/servers/main.py, and src/mcp_atlassian/servers/dependencies.py; validate_url_for_ssrf returns only a verdict rather than a pinned IP, UserTokenMiddleware processes the attacker-controlled headers before fetcher creation, and the Jira and Confluence fetchers use the raw hostname. This issue is fixed in version 0.22.0.

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Meta Information

Published
2026-09-14
Last Modified
2026-09-14
Generated
2026-09-15
AI Q&A
2026-09-14
EPSS Evaluated
N/A
NVD
CVE-2026-73497
EUVD
EUVD-2026-77799

Affected Vendors & Products

Showing 4 associated CPEs
Vendor Product Version / Range
atlassian mcp From 0.17.0 (inc) to 0.22.0 (inc)
atlassian confluence *
atlassian jira *
sooperset mcp-atlassian to 0.22.0 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-918 The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

Attack-Flow Graph

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Executive Summary

MCP Atlassian is a server for Atlassian products like Confluence and Jira. Between versions 0.17.0 and 0.22.0, it had a vulnerability where attacker-controlled headers could bypass security checks. The system validated URLs once but used raw hostnames later, allowing DNS rebinding attacks to redirect requests to internal services or cloud metadata.

Detection Guidance

To detect this vulnerability, check if your mcp-atlassian version is below 0.22.0. Run: pip show mcp-atlassian. If the version is older, the system is vulnerable. Monitor network traffic for unexpected outbound requests to internal or cloud metadata IPs (e.g., 169.254.169.254). Use tools like tcpdump or Wireshark to inspect DNS resolutions and connection attempts.

Impact Analysis

An attacker could exploit this to make unauthorized requests to internal services or cloud metadata endpoints. This could lead to data leaks, unauthorized access, or further attacks within your network if internal services are exposed.

Compliance Impact

This vulnerability could lead to unauthorized access or data breaches, violating GDPR (data protection) and HIPAA (health data privacy). Compliance requires protecting sensitive data, and this flaw could expose such data, risking legal penalties and reputational damage.

Mitigation Strategies

Upgrade MCP Atlassian to version 0.22.0 or later to address the SSRF vulnerability in URL validation and request handling.

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