Update October 23, 2026 : CISA has updated this Alert to: (1) provide a SIGMA detection rule to help identify potentially suspicious activity; (2) incorporate partner resources; and (3) reinforce existing mitigation guidance. Purpose CISA strongly urges organizations to immediately patch the recently disclosed critical vulnerabilities in PHP, CVE-2026-109618 and CVE-2026-109619 . These vulnerabilities, known as “php2shell,” allow for unauthenticated remote code execution in PHP. The vulnerabilities affect all PHP installations serving web requests, including Apache with mod_php ( Note : PHP co