mcp-atlassian Credential Leak via Hint Parameter Injection (CVE-2026-27825/27826) - ATR-2026-00212 (15cda080-5e0c-5456-9ca5-4ad53383bf36)
Detects the mcp-atlassian credential-leak attack pattern (CVE-2026-27825 and CVE-2026-27826). The jira_cloud_id and confluence_spaces MCP tools accept a "hint" parameter that is forwarded verbatim to the LLM context without sanitization. A malicious hint containing a directive to echo request headers (cookie, Authorization, X-API-Key) coerces the agent into leaking the active Atlassian OAuth session cookie or API token back in a follow-up message. CVE-2026-27825 covers the Jira tool surface; CVE-2026-27826 covers Confluence. Both share the same sink. Patched in mcp-atlassian 0.17.0. Publicly resurfaced as "MCPwnfluence" by Pluto Security in April 2026. Disclosed 2026-02-24, resurfaced 2026-04-17.