CVE-2026-77255
CVE-2026-77255
8.6
HighPublished:
Last updated:
Source:security-advisories@github.com
Analyzed
Weakness (CWE)
CVSS Vector
v3.1- Attack Vector
- Network
- Attack Complexity
- Low
- Privileges Required
- None
- User Interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- None
- Availability
- None
Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the Jira update_issue attachments argument is converted into local paths and routed to the attachment upload implementation without workspace validation. A caller can make the MCP server read arbitrary local files and attach them to a Jira issue, using the server as a confused deputy to exfiltrate the contents. The advisory traces the vulnerable input and processing flow through jira update_issue, attachments, upload_attachment, and file_path, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
References
security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/pull/1448security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwc134c704f-9b21-4f2e-91b3-4a467353bcc0
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-2xj6-xx86-cwwc