MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, JiraUserMixin._lookup_user_by_permissions uses the module-level requests.get function instead of the fetcher's protected session. A caller-controlled public Jira URL can redirect that unhooked request to an internal address, bypassing the redirect checks added for CVE-2026-27826.
The advisory traces the vulnerable input and processing flow through JiraUserMixin._lookup_user_by_permissions, requests.get, self.jira._session.get, 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
Low
Easy to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
None
No 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-v9m3-wfh8-5…
security-advisories@github.com