ET WEB_SPECIFIC_APPS Splunk Enterprise Authentication REST API Authenticated Client-Side DoS (CVE-2026-20139)

alert http any any -> [$HOME_NET,$HTTP_SERVERS] any (
    msg:"ET WEB_SPECIFIC_APPS Splunk Enterprise Authentication REST API Authenticated Client-Side DoS (CVE-2026-20139)";
    flow:established,to_server;
    http.uri;
    content:"/splunkd/__raw/services/authentication/users/username"; fast_pattern;
    pcre:"/^.*?(?:realname|tz|email)\x3d[^&]{64,}/R";
    reference:url,advisory.splunk.com/advisories/SVD-2026-0204;
    classtype:attempted-dos;
    sid:2069968; rev:1;
    metadata:affected_product Splunk, attack_target Server, tls_state TLSDecrypt, created_at 2026_06_16, cve CVE_2026_20139, deployment Perimeter, deployment Internal, deployment SSLDecrypt, confidence High, signature_severity Major, tag Exploit, updated_at 2026_06_16, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application;
    target:dest_ip;
)