CVE-2026-77249
MCP Atlassian
- Severity
- Medium
- Published
- September 22, 2026
- Last modified
- September 29, 2026
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.
CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness
- CWE-918 Server-side request forgery
References
- github.comPatch
- github.comIssue TrackingPatch
- github.comRelease Notes
- github.comExploitVendor Advisory
Listed in
More MCP Atlassian CVEs
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.
The OAuth error query parameter is passed to CallbackHandler._send_response in oauth_setup.py and interpolated into an HTML page without escaping.
Validate_safe_path defaults its base directory to os.getcwd(), and affected Confluence attachment call sites omit base_dir, allowing attacker-selected writes within the working directory.
The Jira and Confluence attachment upload tools treat caller-controlled file_path values as trusted server-local paths.
The remediation for CVE-2026-27825 protects download destinations but does not constrain source paths used by attachment uploads.
The OAuth fallback token directory and JSON file are created without explicit owner-only modes.