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Fencer Intel
critical 9.1

CVE-2026-121930 json

Linksys WRT54GL Ping Diagnostic apply.cgi system os command injection

published 5d ago modified 9h ago also EUVD-2026-117019

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.7%
EPSS 2.7% chance of exploitation in 30 days, percentile 86%
public exploits
0
none known

Summary

A weakness has been identified in Linksys WRT54GL 4.30.18. The affected element is the function system of the file apply.cgi of the component Ping Diagnostic. This manipulation of the argument ping_ip causes os command injection. The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks. 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.

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
9h ago

Exploit prediction

2.72% chance of exploitation in the next 30 days, higher than 86% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • github.com https://github.com/Zimo-666/WRT54GL-cves/tree/main/CVE-TBD-ping-ip-command-injection referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.4 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
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA 3.0 9.1 CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R
CNA 2.0 8.3 AV:N/AC:L/Au:M/C:C/I:C/A:C/E:POC/RL:ND/RC:UR
CNA 4.0 8.5 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/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CNA 2.0 8.3 AV:N/AC:L/Au:M/C:C/I:C/A:C

Affected products

  • Linksys WRT54GL

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS Command
  • CWE-77 Improper Neutralization of Special Elements used in a Command

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.