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Fencer Intel
high 8.2

CVE-2018-3969 json

An exploitable vulnerability exists in the verified boot protection of the CUJO Smart Firewall.

published 2019-03-21 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-15755

cvss
8.2
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

An exploitable vulnerability exists in the verified boot protection of the CUJO Smart Firewall. It is possible to add arbitrary shell commands into the dhcpd.conf file, that persist across reboots and firmware updates, and thus allow for executing unverified commands. To trigger this vulnerability, a local attacker needs to be able to write into /config/dhcpd.conf.

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • talosintelligence.com https://talosintelligence.com/vulnerability_reports/TALOS-2018-0634 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.0 8.2 CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

Affected products

  • n/a CUJO

Classification

Weakness
  • CWE-78 Improper Neutralization of Special Elements used in an OS 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.