CVE-2026-77246High· 7.4▾ TwilightMCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, an HTTP transport deployment with READ_ONLY_MODE=false accepts a request without an Authorization identity and permits …
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 40.7 · likelihood 0 · exploitation 0
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MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, an HTTP transport deployment with READ_ONLY_MODE=false accepts a request without an Authorization identity and permits attacker-controlled Atlassian service headers, including X-Atlassian-Confluence-Url, to select a public attacker hostname or one allowed by MCP_ALLOWED_URL_DOMAINS. A caller can then invoke confluence_upload_attachment or the Jira attachment variant in src/mcp_atlassian/jira/attachments.py with a server-local file_path and cause the MCP process to send the file to the selected attachment endpoint. This issue is fixed in version 0.22.0.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
mcp-atlassian < 0.22.0Patched in:
mcp-atlassian 0.22.0Connected by shared product, vendor, weakness, or advisory.
CVE-2026-77255High· 8.6MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)
CVE-2026-77257High· 8.3MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)
CVE-2026-77262High· 8.6MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)
CVE-2026-77266Medium· 6.5MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)
CVE-2026-77269Medium· 6.5MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)
CVE-2026-77259High· 7.7MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)