What’s Vulnerable › Vulnerabilities

CVE-2021-3831: Cross-site Scripting (XSS) - Reflected in gnuboard/gnuboard5

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-12-14 · updated 2026-06-17
• Weakness: CWE-79

Description

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

Affected products

• Gnuboard5: before 5.4.20 — fixed in 5.4.20

How to fix

Upgrade to a fixed version: Gnuboard5 5.4.20. Check the vendor advisory for mitigations.

References

• https://github.com/gnuboard/gnuboard5/commit/2e81619ea87bc9c0b4a073d8df3c7693a6fdbf0d
• https://huntr.dev/bounties/25775287-88cd-4f00-b978-692d627dff04
• https://github.com/gnuboard/gnuboard5/commit/2e81619ea87bc9c0b4a073d8df3c7693a6fdbf0d
• https://huntr.dev/bounties/25775287-88cd-4f00-b978-692d627dff04

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