sooperset mcp-atlassian up to 0.21.x Authentication Header Processing _process_authentication_headers X-Atlassian-Jira-Url/X-Atlassian-Confluence-Url server-side request forgery

Summaryinfo

A vulnerability, which was classified as critical, was found in sooperset mcp-atlassian up to 0.21.x. Impacted is the function _process_authentication_headers of the component Authentication Header Processing. Such manipulation of the argument X-Atlassian-Jira-Url/X-Atlassian-Confluence-Url leads to server-side request forgery. This vulnerability is listed as CVE-2026-77267. The attack may be performed from remote. There is no available exploit. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in sooperset mcp-atlassian up to 0.21.x and classified as critical. Affected by this issue is the function _process_authentication_headers of the component Authentication Header Processing. The manipulation of the argument X-Atlassian-Jira-Url/X-Atlassian-Confluence-Url with an unknown input leads to a server-side request forgery vulnerability. Using CWE to declare the problem leads to CWE-918. The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. Impacted is confidentiality, integrity, and availability. CVE summarizes:

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, 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. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. This issue is fixed in version 0.22.0.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-77267 since 08/20/2026. The exploitation is known to be easy. The attack may be launched remotely. Technical details are known, but there is no available exploit.

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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