CVE-2026-77248
8.6
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Exploitability: 3.9 / Impact: 4.0
Source: security-advisories@github.com (Secondary)
Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the streamable HTTP transport accepts requests without a user identity and falls back to operator credentials, while upload_attachment accepts an unrestricted file_path. An unauthenticated network caller can read files available to the MCP process, upload them to an attacker-selected Jira issue or Confluence page, and retrieve the contents. The advisory traces the vulnerable input and processing flow through streamable-http, UserTokenMiddleware, upload_attachment, file_path, and _get_fetcher, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Affected (1)
Products: Mcp Atlassian: Mcp Atlassian
Configuration A
| Vulnerable Software | Affected Versions |
|---|---|
| version < 0.22.0 |
Related CWEs
CWE-22
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
CWE-306
Missing Authentication for Critical Function
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
References (5)
Source: security-advisories@github.com
Patch
Source: security-advisories@github.com
Issue TrackingPatch
Source: security-advisories@github.com
Release Notes
Source: security-advisories@github.com
Vendor Advisory
Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
Vendor Advisory
Timeline
No history available yet.