CVE-2024-40891: Zyxel DSL CPE OS Command Injection Vulnerability

Vulnerability summary

CVE-2024-40891 is a high (CVSS 8.8) OS Command Injection vulnerability in Zyxel DSL CPE Devices. It is known to be exploited: CISA lists it, first on 11-02-2025. EPSS estimates a 21.70% chance of exploitation in the next 30 days, higher than 97.6% of scored vulnerabilities.

Timeline

1. 04-02-2025
   PublishedVulnerability first disclosed.
2. 11-02-2025
   Added to CISA KEVZyxel DSL CPE OS Command Injection Vulnerability
3. 04-03-2025
   CISA remediation dueApply mitigations per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

Description

**UNSUPPORTED WHEN ASSIGNED** A post-authentication command injection vulnerability in the management commands of the legacy DSL CPE Zyxel VMG4325-B10A firmware version 1.00(AAFR.4)C0_20170615 could allow an authenticated attacker to execute operating system (OS) commands on an affected device via Telnet.

• CWE-78Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.