Zyxel has patched a zero-day vulnerability that attackers exploited to compromise 996 GS1900 network switches across 48 countries, exposing device configurations, network information and hashed root credentials. The attack began around August 17, according to cybersecurity firm GreyNoise, but researchers initially blamed a different vulnerability that Zyxel had already addressed.
The newly identified flaw, tracked as CVE-2026-107441, is a CVSS 8.8 out-of-bounds write vulnerability in the switches’ web management interface. It allows unauthenticated attackers with network access to execute operating system commands through specially crafted HTTP requests.
The flaw affects ten GS1900 models, including GS1900-8, GS1900-24, and GS1900-48. Zyxel listed firmware versions ending in .2C0 and earlier as vulnerable, with model-specific fixes in versions ending in .3C0.
