CVE-2021-3831
Cross-site Scripting (XSS) - Reflected in gnuboard/gnuboard5
gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Cross-site Scripting (XSS) - Reflected in gnuboard/gnuboard5
gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
CVE-2021-3831- CVSS 3.0
- 7.1 High
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2021-27078
gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
EUVD-2021-27078- CVSS 3.0
- 7.1 High
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-xq54-j4gh-pm4j No score
gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross...
gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
GHSA-xq54-j4gh-pm4j- Weakness
- CWE-79
- Updated
- 2026-11-02
NVD
gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
CVE-2021-3831- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - CVSS 3.0
- 7.1 High
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
gnuboard5 is vulnerable to Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- Record
CVE-2021-3831- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - Updated
- 2026-11-02
Affected products
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| Nuclei | Gnuboard 5 - Cross-Site Scripting | |
| PoC in GitHub | aratane/CVE-2021-3831 | 2024-07-20 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, Nuclei, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-3831 is a high vulnerability (CVSS 7.1) in Gnuboard Gnuboard/gnuboard5, published December 14, 2021. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 1.84%, the 79th percentile. No source names a fixed version.