Most business owners never think about the network switch humming away in a closet. Attackers do. According to The Hacker News’ weekly recap published November 9, 2026, a previously unknown flaw in Zyxel GS1900 series switches was exploited to compromise roughly 1,000 devices worldwide. Zyxel has since released a fix.
What happened
The flaw, tracked as CVE-2026-107441 and rated 8.8 on the CVSS severity scale, is an out-of-bounds write. An attacker who is already on the local network and has no login could send a specially crafted web request to the switch and potentially run operating system commands on it. The report says the attacker stole configuration files and credentials from affected devices and installed a backdoor and a rootkit. The activity is attributed to a Chinese-speaking threat actor tracked as Kapibala, also known as Red Heron.
Why it matters for small businesses
Network equipment is often installed once and forgotten. Switches, routers, and firewalls rarely get firmware updates on a schedule, yet they sit at the center of your network and can hold passwords and configuration details. A compromised switch gives an intruder a quiet foothold that antivirus on your computers will not see. Because this attack requires local network access, it also shows why keeping unknown devices and guests off your main network matters.
Practical steps
- Make a list of every switch, router, and firewall on your network, including make, model, and firmware version.
- If you use Zyxel GS1900 switches, check Zyxel’s advisory and install the fixed firmware.
- Turn off web management access on devices that do not need it, and restrict it to a dedicated management network or specific computers.
- Change default and shared admin passwords, and consider changing credentials on any device that may have been exposed.
- Put guest Wi-Fi and visitor devices on a separate network from your business systems.
Not sure what is plugged into your network or whether it is up to date? Call Arete Technology Systems at (317) 585-6100 and we will help you take stock.