alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET WEB_SPECIFIC_APPS Kestra Unauthenticated Remote Code Execution (CVE-2026-53576)"; flow:established,to_server; http.uri; content:"/api/v1/main/flows/configs"; fast_pattern; http.request_body; content:"namespace|3a 20|configs"; content:"io.kestra.plugin.scripts.shell.Commands"; content:"commands|3a|"; http.method; content:"POST"; reference:url,github.com/kestra-io/kestra/security/advisories/GHSA-2q47-568g-9h4f; reference:cve,2026-53576; classtype:web-application-attack; sid:2071777; rev:1; metadata:attack_target Server, tls_state TLSDecrypt, created_at 2026_08_24, cve CVE_2026_53576, deployment Perimeter, deployment Internal, confidence High, signature_severity Major, tag Exploit, updated_at 2026_08_24, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)