CVE-2024-40891
Published: February 11, 2025
Official Description
Multiple Zyxel DSL CPE devices contain a post-authentication command injection vulnerability in the management commands that could allow an authenticated attacker to execute OS commands via Telnet.
CISA KEV Advisory
Zyxel DSL CPE OS Command Injection Vulnerability
Multiple Zyxel DSL CPE devices contain a post-authentication command injection vulnerability in the management commands that could allow an authenticated attacker to execute OS commands via Telnet.
The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization if a current mitigation is unavailable.
Risk Analysis
Multiple Zyxel DSL CPE devices contain a post-authentication command injection vulnerability that allows an authenticated attacker to execute OS commands via Telnet. The high EPSS score and confirmed exploitation by CISA indicate a significant risk, especially if management interfaces are exposed.
This vulnerability has been actively exploited in the wild. Exploitation requires prior authentication, but once authenticated, an attacker can execute arbitrary OS commands remotely via Telnet.
Administrators should apply available firmware updates for affected Zyxel DSL CPE devices. Restrict Telnet access to these devices and ensure strong, unique credentials are used for management interfaces.
Technical Analysis
CVE-2024-40891 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2024-40891 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Exploit & PoC Resources
All References (3)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2024-40891 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1