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

Status: published. Published: 2026-11-04. Updated: 2026-11-04.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linksys / WRT54GL: 4.30.18 (affected). Source: CNA: VulDB

## Severity and prioritization

- CVSS 4.0: 9.4 (critical); CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P; source: CNA: VulDB

- CVSS 3.1: 9.1 (critical); CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 3.0: 9.1 (critical); CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:C; source: CNA: VulDB

- CVSS 2.0: 8.3 (high); AV:N/AC:L/Au:M/C:C/I:C/A:C/E:POC/RL:ND/RC:C; source: CNA: VulDB

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-78, CWE-77

## Exploit evidence

- exploit: https://github.com/Zimo-666/WRT54GL-cves/tree/main/CVE-TBD-traceroute-ip-command-injection (CNA: VulDB)

## References

- https://vuldb.com/vuln/431043 (CNA: VulDB; vdb-entry, technical-description)

- https://vuldb.com/vuln/431043/cti (CNA: VulDB; signature, permissions-required)

- https://vuldb.com/cve/CVE-2026-121931 (CNA: VulDB; third-party-advisory)

- https://vuldb.com/submit/1024099 (CNA: VulDB; third-party-advisory)

- https://github.com/Zimo-666/WRT54GL-cves/tree/main/CVE-TBD-traceroute-ip-command-injection (CNA: VulDB; exploit)

- https://www.linksys.com/ (CNA: VulDB; product)

## Provenance

- CNA: VulDB: https://www.cve.org/CVERecord?id=CVE-2026-121931; retrieved 2026-11-04; source updated 2026-11-04

Revision: cf1ab78a29b6b56fd7bc4df9d4111f7316321f7017b764f90bbcc27132c49263

Canonical: https://y2.dev/cve/CVE-2026-121931

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