CXO Daily Cybersecurity Intelligence Brief For May 19, 2026

A Microsoft Exchange zero-day, a new npm supply chain compromise, and a GitHub token breach are putting enterprise communications, developer trust, and source code integrity under renewed pressure. In today's CXO Daily Cybersecurity Intelligence Briefing, we examine active exploitation of CVE-2026-42897, a cross-site scripting vulnerability targeting Outlook Web Access with no patch currently available. For CISOs, CIOs, risk leaders, and boards, the exposure raises urgent concerns around email security, credential theft, regulatory obligations, and the operational risks of on-prem Exchange environments. The episode also covers a software supply chain attack involving Mini Shai-Hulud malware and a compromised npm maintainer account tied to the AntV library, highlighting how privileged developer credentials can create downstream risk across finance, e-commerce, and technology environments. We also unpack Grafana Labs' GitHub token breach, the implications of source code exposure, and the need for stronger secret management, token lifecycle controls, and supplier assurance. Additional developments include ongoing healthcare data breaches, a macOS infostealer posing as Apple security updates, and Poland's move away from Signal for government communications. Stay informed on the latest cybersecurity threats, cyber risk trends, and leadership implications shaping enterprise resilience.