CVE-2026-77274

MCP Atlassian: SSRF Protection Bypass

Published Sep 22, 2026 CVSS 4.0 · 8.8 High EPSS < 1% KEV · Not listed
Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, validate_url_for_ssrf has a backslash authority confusion because it interprets the authority differently from the Requests connection layer in the header-based Jira and Confluence URL authentication flow. A crafted URL can validate as an external hostname while the HTTP client connects to an internal host, permitting server-side requests to protected network resources. This issue is fixed in version 0.22.0.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-hgcf-4mq8-5266 MCP Atlassian: SSRF Protection Bypass
History
Type Values Removed Values Added
First Time appeared Mcp-atlassian
Mcp-atlassian mcp Atlassian
CPEs cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:*
Vendors & Products Mcp-atlassian
Mcp-atlassian mcp Atlassian
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Sooperset
Sooperset mcp-atlassian
Vendors & Products Sooperset
Sooperset mcp-atlassian
Type Values Removed Values Added
Description MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, validate_url_for_ssrf has a backslash authority confusion because it interprets the authority differently from the Requests connection layer in the header-based Jira and Confluence URL authentication flow. A crafted URL can validate as an external hostname while the HTTP client connects to an internal host, permitting server-side requests to protected network resources. This issue is fixed in version 0.22.0.
Title MCP Atlassian: SSRF Protection Bypass
Weaknesses CWE-918
References
Metrics cvssV4_0

{'score': 8.8, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 22, 2026, 6:32 PM
Reserved
Aug 20, 2026, 7:14 PM
Status
Analyzed
Published
Sep 22, 2026, 6:17 PM
Modified
Sep 28, 2026, 1:41 PM