Linksys WRT54GL 4.30.18 Ping Diagnostic apply.cgi system ping_ip os command injection

Summaryinfo

A vulnerability labeled as very critical has been found in Linksys WRT54GL 4.30.18. The impacted element is the function system of the file apply.cgi of the component Ping Diagnostic. Such manipulation of the argument ping_ip leads to os command injection. This vulnerability only affects products that are no longer supported by the maintainer. This vulnerability is uniquely identified as CVE-2026-121930. The attack can be launched remotely. Moreover, an exploit is present. The vendor was contacted early about this disclosure but did not respond in any way.

Detailsinfo

A vulnerability was found in Linksys WRT54GL 4.30.18 and classified as very critical. Affected by this issue is the function system of the file apply.cgi of the component Ping Diagnostic. The manipulation of the argument ping_ip with an unknown input leads to a os command injection vulnerability. Using CWE to declare the problem leads to 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. Impacted is confidentiality, integrity, and availability.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-121930. The exploitation is known to be easy. The attack may be launched remotely. Additional levels of successful authentication are required for exploitation. Technical details as well as a public exploit are known. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 11/04/2026). This vulnerability is assigned to T1202 by the MITRE ATT&CK project.

The exploit is available at github.com. It is declared as proof-of-concept. The vendor was contacted early about this disclosure but did not respond in any way.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Router Operating System

Vendor

• Linksys

Name

• WRT54GL

Version

• 4.30.18

License

• commercial

Support

• end of life

Website

• Vendor: https://www.linksys.com/

CPE 2.3info

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CPE 2.2info

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Submitinfo

Accepted

• Submit #1024098: Linksys WRT54GL 4.30.18 OS Command Injection (CWE-78) (by liuyingqi)

If you want to get best quality of vulnerability data, you may have to visit VulDB.

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