sooperset mcp-atlassian up to 0.21.x Streamable HTTP Transport upload_attachment file_path information disclosure

Summaryinfo

A vulnerability categorized as problematic has been discovered in sooperset mcp-atlassian up to 0.21.x. This impacts the function upload_attachment of the component Streamable HTTP Transport. Such manipulation of the argument file_path leads to information disclosure. This vulnerability is documented as CVE-2026-77248. The attack can be executed remotely. There is not any exploit available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in sooperset mcp-atlassian up to 0.21.x. It has been rated as problematic. Affected by this issue is the function upload_attachment of the component Streamable HTTP Transport. The manipulation of the argument file_path with an unknown input leads to a information disclosure vulnerability. Using CWE to declare the problem leads to CWE-200. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. Impacted is confidentiality. CVE summarizes:

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.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-77248 since 08/20/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1592 by the MITRE ATT&CK project.

Upgrading to version 0.22.0 eliminates this vulnerability.

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Productinfo

Type

• Artificial Intelligence Software

Vendor

• sooperset

Name

• mcp-atlassian

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9
• 0.10
• 0.11
• 0.12
• 0.13
• 0.14
• 0.15
• 0.16
• 0.17
• 0.18
• 0.19
• 0.20
• 0.21

Website

• Product: https://github.com/sooperset/mcp-atlassian/

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