CVE-2025-66121: Siteground Security

Medium severity, CVSS 5.3. EPSS: 0.3% chance of exploitation in the next 30 days.

Missing Authorization vulnerability in SiteGround SiteGround Security sg-security allows Exploiting Incorrectly Configured Access Control Security Levels.This issue affects SiteGround Security: from n/a through <= 1.5.8.

Affected products

• Siteground Siteground Security: up to and including 1.5.8

Published 2025-12-16. Last modified 2026-06-17.