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CVE-2026-121931

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

  • Critical 9.4
  • A public exploit reference is listed

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.

Key facts

Published
4 Nov 2026
Last changed
9 Nov 2026
Assigned by
VulDB
EPSS
2.722% likely to be exploited in the next 30 days, higher than 86.282% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: poc; Automatable: no; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 9.4CVSS 4.0, Criticalfrom the CNA (VulDB)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
  • 9.1CVSS 3.1, Criticalfrom the CNA (VulDB)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
  • 9.1CVSS 3.0, Criticalfrom the CNA (VulDB)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
  • 8.3CVSS 2.0, Highfrom the CNA (VulDB)AV:N/AC:L/Au:M/C:C/I:C/A:C/E:POC/RL:ND/RC:C

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
LinksysWRT54GL
  • 4.30.18 (affected)

Timeline

  1. 4 Nov 2026 Advisory disclosed
  2. 4 Nov 2026 VulDB entry created
  3. 4 Nov 2026 VulDB entry last update
  4. 4 Nov 2026 Published

Weakness

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References