GFI MailEssentials AI < 22.4 Attachment Filtering Rule - Stored XSS Severity MEDIUM Date 2/19/2026 CVE CVE-2026-23605 CVSS V4 Vector CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/L:V/A:N/SC:L/SI:L/SA:N References GFI MailEssentials Release Notes Credit Alex Williams from Peller Technologies Description GFI MailEssentials AI versions prior to 22.4 contain a stored cross-site scripting vulnerability in the Attachment Filtering rule creation workflow. An authenticated user can supply HTML/JavaScript in the ctl00$ContentPlaceHolder1$pv1$TXB_RuleName parameter to /MailEssentials/pages/MailSecurity/attachmentchecking.aspx, which is stored and later rendered in the management interface, allowing script execution in the context of a logged-in user.