CVE-2026-77257
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, HTTP-exposed Jira and Confluence upload tools pass a caller-provided file_path to local file operations without restricting it to the workspace. A remote MCP caller with tool access can cause the server to read sensitive local files and upload them as Atlassian attachments. The advisory traces the vulnerable input and processing flow through streamable-http, upload_attachment, and file_path, 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.comVendor 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.