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CVE-2026-121931— Linksys WRT54GL Traceroute Diagnostic Function apply.cgi system os command injection

Quick assessment

Affected

Linksys WRT54GL

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linksys WRT54GL 固件版本 4.30.18 中发现一个安全漏洞。受影响的组件是"Traceroute 诊断功能”，具体位于 apply.cgi 文件中的 system 函数。攻击者可通过操纵 traceroute_ip 参数触发操作系统命令注入。该攻击可远程发起。利用方法已被公开披露，可能被恶意利用。厂商虽在披露早期即被联系，但始终未作出任何回应。此漏洞仅影响已不再由维护者提供支持的产品。

CVSS 9.1 · Critical Updated Nov 05, 2026

Possible ATT&CK Techniques 2 AI

T1059 · Command and Scripting Interpreter T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

Vendor	Product	Version Range	Status
Linksys	WRT54GL	`4.30.18`	affected

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Vulnerability Information

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Vulnerability Title

Linksys WRT54GL Traceroute Diagnostic Function apply.cgi system os command injection

Source: CVE Program / CVE List V5

Vulnerability Description

A security vulnerability has been detected in Linksys WRT54GL 4.30.18. The impacted element is the function system of the file apply.cgi of the component Traceroute Diagnostic Function. Such manipulation of the argument traceroute_ip leads to os command injection. The attack can be launched remotely. The exploit has been disclosed publicly and may be used. The vendor was contacted early about this disclosure but did not respond in any way. This vulnerability only affects products that are no longer supported by the maintainer.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

OS命令中使用的特殊元素转义处理不恰当(OS命令注入)

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
Linksys	WRT54GL	4.30.18	`cpe:2.3:h:linksys:wrt54gl::::::::`

II. Public POCs for CVE-2026-121931

#	POC Description	Source Link	Shenlong Link

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No public POC found.

III. Intelligence Information for CVE-2026-121931

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Vendor Advisories for CVE-2026-121931 (1)

CVE-2026-121931 | Linksys WRT54GL 4.30.18 Traceroute Diagnostic Function apply.cgi system traceroute_ip os command injection vdb-entry technical-description

Other References for CVE-2026-121931 (4)

https://github.com/Zimo-666/WRT54GL-cves/tree/main/CVE-TBD-traceroute-ip-command-injection exploit
https://vuldb.com/cve/CVE-2026-121931 third-party-advisory
https://vuldb.com/vuln/431043/cti signature permissions-required
https://vuldb.com/submit/1024099 third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-121931

Same Patch Batch · Linksys · 2026-11-04 · 8 CVEs total

CVE-2026-121615	10.0 CRITICAL	Linksys E5600 Login mesh_login.cgi improper authentication
CVE-2026-121932	10.0 CRITICAL	Linksys E5350 apply.cgi system os command injection
CVE-2026-121933	10.0 CRITICAL	Linksys E5350 Setup Wizard apply.cgi save_settings missing authentication
CVE-2026-121930	9.1 CRITICAL	Linksys WRT54GL Ping Diagnostic apply.cgi system os command injection
CVE-2026-121617	7.5 HIGH	Linksys E5600 Header upload_fw.cgi init_multipart out-of-bounds write
CVE-2026-121616	5.3 MEDIUM	Linksys E5600 JSON Request mesh_login.cgi strcpy out-of-bounds write
CVE-2026-121618	5.3 MEDIUM	Linksys E5600 Factory Quality Control fqc.cgi information disclosure

IV. Related Vulnerabilities

Same product: WRT54GL

Same vendor: Linksys

Same weakness: CWE-78