Key points
- The flaw exists in Linksys E1700 firmware version 1.0.0.4.003.
- Attackers can exploit the setLinksysIpv6 function remotely.
- The vendor has not responded to disclosure attempts.
A critical security vulnerability has been identified in the Linksys E1700 router, specifically within firmware version 1.0.0.4.003. The issue allows remote attackers to execute arbitrary operating system commands on the device. This flaw is classified as critical with a CVSS score of 9.4, indicating a severe risk to network security and device integrity.
In plain English
The vulnerability stems from how the router processes IPv6 configuration data. The specific function involved is setLinksysIpv6, located in the file /goform/setLinksysIpv6. When this function handles arguments related to _6rd_prefix or _6rd_prefix_len, it fails to properly sanitize the input. This lack of validation allows an attacker to inject malicious operating system commands, which the router then executes.
The background
According to the National Vulnerability Database record, the weaknesses are categorized as CWE-78 and CWE-77. The source material lists these identifiers but does not provide their textual definitions. The exploit method has been made public, meaning the code or instructions needed to abuse this flaw are available. The vendor was contacted early regarding this disclosure but did not respond in any way.
What changes now
With the exploit code publicly available, the risk of active abuse is elevated. Security teams should treat this as an immediate threat to any network using the affected firmware version. Since the vendor has not provided a patch or update, users remain exposed to remote code execution attacks. No fix has been confirmed yet, leaving administrators to consider alternative mitigation strategies or hardware replacement.
What to do and how to stay safe: Linksys
- Isolate affected Linksys E1700 routers from the internet immediately to prevent remote exploitation.
- Monitor network traffic for unusual outbound connections or command execution patterns indicative of compromise.
- Review firewall rules to block unsolicited traffic targeting the router's administrative interfaces.
- Plan for hardware replacement or firmware downgrade if a secure older version is available and stable.
Step-by-step guide: 7 Configuration Errors That Expose Systems to Zero-Day Exploits
General security guidance from the Vuln Post newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
Which specific firmware version is affected?
The vulnerability affects Linksys E1700 firmware version 1.0.0.4.003.
Is there a patch available for this flaw?
No, the vendor did not respond to disclosure attempts and no fix has been confirmed.
How is the attack launched?
The attack can be launched remotely by manipulating the _6rd_prefix or _6rd_prefix_len arguments.
