SolarWinds Web Help Desk (WHD) is under attack, with recent incidents exploiting a chain of zero-day and patched vulnerabilities dating back to late 2025, an analysis of customer reports by security company Huntress has found. Until now, it has been unclear which combination of recent WHD vulnerabilities were behind a series of compromises of customer systems first uncovered in December. On January 28, SolarWinds published an advisory that mentioned six CVEs rated either ‘critical’ or ‘high.’ These included two zero-days with a CVSS score of 9.8: CVE-2025-40551, a deserialization flaw allowing remote code execution (RCE), and CVE-2025-40536, an authentication bypass. Even the Microsoft Defen...