CVE-2026-77249

MCP Atlassian: Incomplete fix for CVE-2026-27826: redirect-based SSRF via unhooked requests session in Jira user-permission lookup

Published Sep 22, 2026 CVSS 3.1 · 5.3 Medium 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, 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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-v9m3-wfh8-5646 MCP Atlassian: Incomplete fix for GHSA-7r34-79r5-rcc9: redirect-based SSRF via unhooked requests session in Jira user-permission lookup
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
Type Values Removed Values Added
First Time appeared Sooperset
Sooperset mcp-atlassian
Vendors & Products Sooperset
Sooperset mcp-atlassian
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

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, 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.
Title MCP Atlassian: Incomplete fix for CVE-2026-27826: redirect-based SSRF via unhooked requests session in Jira user-permission lookup
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 22, 2026, 7:36 PM
Reserved
Aug 20, 2026, 7:02 PM
Status
Analyzed
Published
Sep 22, 2026, 7:16 PM
Modified
Sep 29, 2026, 6:59 PM