CVE-2021-3831: Gnuboard GNUBOARD5

Medium severity, CVSS 6.1. EPSS: 1.8% chance of exploitation in the next 30 days.

gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Affected products

• Gnuboard GNUBOARD5: before 5.4.20 (fixed in 5.4.20)

Published 2021-12-14. Last modified 2026-06-17.