OpenOlat is an open source web-based e-learning platform for teaching, learning, assessment and communication. Prior to versions 19.1.31, 20.1.18, and 20.2.5, an authenticated user with the Author role can inject Velocity directives into a reminder email template. When the reminder is processed (either triggered manually or via the daily cron job), the injected directives are evaluated server-side. By chaining Velocity's #set directive with Java reflection, an attacker can instantiate arbitrary Java classes such as java.lang.ProcessBuilder and execute operating system commands with the privileges of the Tomcat process (typically root in containerized deployments). This issue has been patched in versions 19.1.31, 20.1.18, and 20.2.5.
Conclusion & alert: CVE-2026-28228 is rated Low Risk (37.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.02%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-22 | 0.05% | 0.02% | -0.03% |
| 2 | 2026-04-03 | 0.05% | 0.05% | +0.00% |
| 3 | 2026-03-31 | — | 0.05% | — |
Full EPSS history (3 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 8.8 | 3.1 | HIGH |
|
2.8 | 5.9 | [email protected] |
| URL | Tags |
|---|---|
| https://github.com/OpenOLAT/OpenOLAT/security/advisories/GHSA-55qg-vvgj-ffh4 | Mitigation Vendor Advisory |