RCE in Linksys Wrt54gl
CVE-2026-121931
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.
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
- Linksys Wrt54gl — versions 4.30.18
Weakness classification (CWE)
References
- vuldb.com/vuln/431043 (technical-description, vdb-entry)
- vuldb.com/vuln/431043/cti (signature, permissions-required)
- vuldb.com/cve/CVE-2026-121931 (third-party-advisory)
- vuldb.com/submit/1024099 (third-party-advisory)
- github.com/Zimo-666/WRT54GL-cves/tree/main/CVE-TBD-traceroute-ip-command-inject… (exploit)
- www.linksys.com/ (product)
Frequently asked questions
- What is CVE-2026-121931?
- CVE-2026-121931 is a critical-severity vulnerability in Linksys Wrt54gl, classified under Command Injection. CVSS score: 9.1/10. Published 2026-11-04.
- How severe is CVE-2026-121931?
- Critical severity. CVSS v3 base score is 9.1 out of 10.