cPanel Session Cookie Truncation (CVE-2026-41940) Detection

Detects truncated 'whostmgrsession' cookies missing the comma delimiter, which is a necessary step for attackers to inject cleartext CRLF payloads into cPanel session files and bypass authentication. This rule specifically looks for the 'whostmgrsession' cookie in web or proxy logs where the cookie value matches a regex pattern indicating the absence of the expected comma delimiter, a characteristic of the CVE-2026-41940 exploitation.