Linksys E900 Service Port 8080 /tmUnblock.cgi ttcp_ip TheMoon os command injection

Summaryinfo

A vulnerability described as critical has been identified in Linksys E4200, E3200, E3000, E2500, E2100L, E2000, E1550, E1500, E1200, E1000 and E900. This impacts an unknown function of the file /tmUnblock.cgi of the component Service Port 8080. Executing a manipulation of the argument ttcp_ip can lead to os command injection. This vulnerability is handled as CVE-2025-34037. The attack can be executed remotely. Additionally, an exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as very critical was found in Linksys E4200, E3200, E3000, E2500, E2100L, E2000, E1550, E1500, E1200, E1000 and E900. This vulnerability affects an unknown code block of the file /tmUnblock.cgi of the component Service Port 8080. The manipulation of the argument ttcp_ip with an unknown input leads to a os command injection vulnerability. The CWE definition for the vulnerability is CWE-78. 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. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

An OS command injection vulnerability exists in various models of E-Series Linksys routers via the /tmUnblock.cgi and /hndUnblock.cgi endpoints over HTTP on port 8080. The CGI scripts improperly process user-supplied input passed to the ttcp_ip parameter without sanitization, allowing unauthenticated attackers to inject shell commands. This vulnerability was reported to be exploited in the wild by the "TheMoon" worm  in 2014 to deploy a MIPS ELF payload, enabling arbitrary code execution on the router. Additionally, this vulnerability may affect other Linksys products to include, but not limited to, WAG/WAP/WES/WET/WRT-series router models and Wireless-N access points and routers. Exploitation evidence was observed by the Shadowserver Foundation on 2025-02-06 UTC.

The weakness was released by Johannes Ullrich. The advisory is shared for download at isc.sans.edu. This vulnerability was named CVE-2025-34037 since 04/15/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details and also a public exploit are known. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 03/20/2026). The MITRE ATT&CK project declares the attack technique as T1202.

It is possible to download the exploit at exploit-db.com. It is declared as highly functional.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Exploit-DB (31683) and EUVD (EUVD-2025-18964). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Router Operating System

Vendor

• Linksys

Name

• E900
• E1000
• E1200
• E1500
• E1550
• E2000
• E2100L
• E2500
• E3000
• E3200
• E4200

License

• commercial

Website

• Vendor: https://www.linksys.com/

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Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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