alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (msg:"ET WEB_SPECIFIC_APPS Kubernetes Secret Extraction via ArgoCD ServerSideDiff (CVE-2026-42880)"; flow:established,to_server; http.uri; content:"/application.ApplicationService/ServerSideDiff"; fast_pattern; http.content_type; content:"application/grpc-web+proto"; http.header; to_lowercase; content:"x-grpc-web|3a 20|1"; http.method; content:"POST"; reference:url,github.com/argoproj/argo-cd/security/advisories/GHSA-3v3m-wc6v-x4x3; reference:cve,2026-42880; classtype:web-application-attack; sid:2071781; rev:1; metadata:affected_product Kubernetes, attack_target Server, tls_state TLSDecrypt, created_at 2026_08_24, cve CVE_2026_42880, 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;)