ACTIVELY EXPLOITED
CVE-2023-33009: Zyxel Multiple Firewalls Buffer Overflow Vulnerability
| Vendor | Zyxel |
|---|---|
| Product | Multiple Firewalls |
| Actively exploited | Yes |
| Added to CISA KEV | 5 Jun 2023 |
| CISA federal deadline | 26 Jun 2023 |
| Weakness (CWE) | CWE-120 |
Required action (CISA's text)
Apply updates per vendor instructions.
Description (NVD)
Zyxel ATP, USG FLEX, USG FLEX 50(W), USG20(W)-VPN, VPN, and ZyWALL/USG firewalls contain a buffer overflow vulnerability in the notification function that could allow an unauthenticated attacker to cause denial-of-service (DoS) conditions and remote code execution on an affected device.
SOURCES
Other Zyxel flaws
- CVE-2026-7273: Zyxel GS1900 Series Switches Stack-Based Buffer Overflow Vulnerability
- CVE-2024-40891: Zyxel DSL CPE OS Command Injection Vulnerability
- CVE-2024-40890: Zyxel DSL CPE OS Command Injection Vulnerability
- CVE-2024-11667: Zyxel Multiple Firewalls Path Traversal Vulnerability
- CVE-2017-6884: Zyxel EMG2926 Routers Command Injection Vulnerability
Data from NVD, CISA KEV, FIRST EPSS and vendor advisories. Updated 10 Nov 2026.