Critical Zero-Day in KnowledgeDeliver LMS Exploited to Deploy Web Shells
In late 2025, attackers exploited a zero-day vulnerability (CVE-2026-5426) in Digital Knowledge's KnowledgeDeliver Learning Management System (LMS). This flaw, stemming from hardcoded ASP.NET machineKey values across deployments, allowed unauthenticated remote code execution via malicious ViewState deserialization. Exploiting this, threat actors deployed the Godzilla (BlueBeam) web shell, enabling further system compromise and the distribution of Cobalt Strike beacons to users through malicious scripts embedded in the platform. This incident underscores the critical risks associated with default configurations and hardcoded cryptographic keys in web applications. The exploitation of such vulnerabilities highlights the necessity for organizations to implement unique, secure configurations and to stay vigilant against emerging threats targeting widely-used platforms.
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