alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS nginx-ui MCP Module Authentication Bypass (CVE-2026-33032)"; flow:established,to_server; http.uri; content:"/mcp_message|3f|"; fast_pattern; content:"sessionid|3d|"; nocase; http.header_names; content:!"cookie|0d 0a|"; nocase; http.method; content:"POST"; reference:url,pluto.security/blog/mcp-bug-nginx-security-vulnerability-cvss-9-8/; reference:cve,2026-33032; classtype:web-application-attack; sid:2068850; rev:1; metadata:attack_target Server, tls_state TLSDecrypt, created_at 2026_04_21, cve CVE_2026_33032, deployment Perimeter, deployment Internal, deployment SSLDecrypt, confidence High, signature_severity Major, tag Exploit, updated_at 2026_04_21, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)