CVE-2026-77269
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, the remediation for CVE-2026-27825 protects download destinations but does not constrain source paths used by attachment uploads. A caller can provide an absolute or traversal file_path and cause the server to upload the selected local file. The advisory traces the vulnerable input and processing flow through upload_attachment, file_path, and CVE-2026-27825, 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:L/UI:N/S:U/C:H/I:N/A:N
Weakness
- CWE-22 Path traversal
References
- github.comPatch
- github.comIssue TrackingPatch
- github.comRelease Notes
- github.comExploitVendor Advisory
- 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 OAuth fallback token directory and JSON file are created without explicit owner-only modes.
The X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf.