Goal Reached Thanks to every supporter — we hit 100%!

Goal: 1000 CNY · Raised: 1336 CNY

100%
Buy Us a Coffee

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

Quick assessment

Affected
gnuboard gnuboard/gnuboard5
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

GNUBOARD5是一套基于PHP和MySQL的Web论坛系统。 gnuboard5 存在跨站脚本漏洞，该漏洞源于在网页生成期间容易受到不正确输入的影响。

AI Predicted 6.1 Difficulty: Easy EPSS 1.81% · P77

Public Exploits 1

Nuclei · 1 CVE-2021-3831.yaml [template]

Possible ATT&CK Techniques 1 AI

T1189 · Drive-by Compromise
Get alerts for future matching vulnerabilities Log in to subscribe

I. Basic Information for CVE-2021-3831

Vulnerability Information
Have questions about the vulnerability? See if Shenlong's analysis helps!
View Shenlong Deep Dive ↗

Although we use advanced large model technology, its output may still contain inaccurate or outdated information.Shenlong tries to ensure data accuracy, but please verify and judge based on the actual situation.

Vulnerability Title
Cross-site Scripting (XSS) - Reflected in gnuboard/gnuboard5
Source: CVE Program / CVE List V5
Vulnerability Description
gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
在Web页面生成时对输入的转义处理不恰当(跨站脚本)
Source: CVE Program / CVE List V5
Vulnerability Title
GNUBOARD5 跨站脚本漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
GNUBOARD5是一套基于PHP和MySQL的Web论坛系统。 gnuboard5 存在跨站脚本漏洞，该漏洞源于在网页生成期间容易受到不正确输入的影响。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
gnuboard gnuboard/gnuboard5 unspecified ~ 5.4.20 -

II. Public POCs for CVE-2021-3831

# POC Description Source Link Shenlong Link
1 Unauthenticated Sensitive Information Disclosure https://github.com/aratane/CVE-2021-3831 POC Details
2 Gnuboard 5 contains a cross-site scripting vulnerability via the $_GET['LGD_OID'] parameter. https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-3831.yaml POC Details
AI-Generated POC Premium

No public POC found.

Login to generate AI POC

III. Intelligence Information for CVE-2021-3831

请登录查看更多情报信息。

Patches & Fixes for CVE-2021-3831 (1)

Vendor Advisories for CVE-2021-3831 (1)

IV. Related Vulnerabilities

Same product: gnuboard/gnuboard5
Same vendor: gnuboard
Same weakness: CWE-79

V. Comments for CVE-2021-3831

Anonymous User
2026-06-25 09:14:29

Here to explore discussions, exchange ideas, and learn something new throughout the journey. I'm interested in understanding different opinions and contributing whenever I can. Happy to hear different experiences and meeting like-minded people. There is my web-site:<a href="https://automisto24.com.ua/">AutoMisto24</a> https://automisto24.com.ua/

Anonymous User
2026-06-25 09:19:01

Happy to dive into discussions, share thoughts, and learn something new along the way. I like hearing diverse viewpoints and contributing whenever I can. Happy to hear different experiences and building connections. Here's my web-site:<a href="https://automisto24.com.ua/">AutoMisto24</a> https://automisto24.com.ua/

Leave a comment