What is CVE-2021-40214?

CVE-2021-40214 is a medium-severity vulnerability in Gibbonedu Gibbon, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-09-13.

How severe is CVE-2021-40214?

Medium severity. CVSS v3 base score is 5.4 out of 10.

XSS in Gibbonedu Gibbon

CVE-2021-40214

Gibbon v22.0.00 suffers from a stored XSS vulnerability within the wall messages component.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2021-09-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (52.6th percentile), scored 2026-09-26.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 52.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Gibbonedu Gibbon — versions 22.0.00

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

gibbonedu.org/ (Product)
github.com/GibbonEdu/core/releases/download/v22.0.00/GibbonEduCore-InstallBundl… (Third Party Advisory)
github.com/GibbonEdu/core/blob/v22.0.01/CHANGELOG.txt (Third Party Advisory)

Frequently asked questions

What is CVE-2021-40214?: CVE-2021-40214 is a medium-severity vulnerability in Gibbonedu Gibbon, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2021-09-13.
How severe is CVE-2021-40214?: Medium severity. CVSS v3 base score is 5.4 out of 10.