Security briefing: May 2026

In May 2026, a series of significant cybersecurity breaches highlighted the persistent vulnerabilities and operational mistakes within major platforms and ecosystems. Notable incidents included the ShinyHunters ransomware group compromising the Canvas learning management platform, a GitHub breach facilitated by a malicious extension in the VS Code Marketplace, and the exposure of AWS GovCloud credentials by a CISA contractor. New attack methods, such as LLM-driven intrusions and the novel NATS-as-C2 command-and-control technique, underscored the evolving threat landscape. The month also saw the rapid exploitation of vulnerabilities, particularly those related to AI, emphasizing the importance of swift detection and response. Despite advancements in attack strategies, many breaches were attributed to basic security lapses like exposed credentials and disabled guardrails, underscoring the need for improved security practices and faster defensive measures to counteract the increased speed and sophistication of modern cyber threats.