CVE Catalog

CVE-2026-77248

HighCVSS 8.6
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.42%

34th percentile - higher than 34% of all known CVEs

Summary

In MCP Atlassian 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.

Risk Assessment

An unauthenticated network attacker can exfiltrate any files readable by the MCP process and upload them to an attacker-controlled location in Atlassian. This constitutes a serious data leak without requiring an account.

Recommendation

Update MCP Atlassian to version 0.22.0 or later. Do not expose the MCP server to network access without authentication and limit the process privileges.

Other vulnerabilities in MCP Atlassian

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS