NfSen before 1.3.8 allows remote attackers to execute arbitrary OS commands via shell metacharacters in the customfmt parameter (aka the "Custom output format" field).
Severity
CVSS 3.0
9.9 critical
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS
6.5% chance of exploitation in the next 30 days; higher than 93% of CVEs (scores of 2026-10-31)