MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, validate_url_for_ssrf checks a hostname's resolved addresses, but Requests and urllib3 resolve the hostname again when connecting. A caller can use a short-lived DNS answer that is public during validation and private during connection, preserving unauthenticated access to internal or metadata endpoints despite the earlier CVE-2026-27826 remediation.
The advisory traces the vulnerable input and processing flow through validate_url_for_ssrf, _check_dns_resolution, socket.getaddrinfo, and _make_ssrf_safe_hook, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Mcp-Atlassian Mcp_Atlassian
cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:*
|
— |
0.22.0
|
References 4
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c2…
security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/pull/1448
security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0
security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-72fm-whvq-j…
security-advisories@github.com