OpenOlat up to 19.1.30/20.1.17/20.2.4 Email Template special elements used in a template engine

Summaryinfo

A vulnerability classified as critical has been found in OpenOlat up to 19.1.30/20.1.17/20.2.4. Affected by this vulnerability is an unknown functionality of the component Email Template Handler. Performing a manipulation results in improper neutralization of special elements used in a template engine. This vulnerability is known as CVE-2026-28228. Remote exploitation of the attack is possible. No exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in OpenOlat up to 19.1.30/20.1.17/20.2.4. It has been classified as critical. This affects some unknown processing of the component Email Template Handler. The manipulation with an unknown input leads to a improper neutralization of special elements used in a template engine vulnerability. CWE is classifying the issue as CWE-1336. The product uses a template engine to insert or process externally-influenced input, but it does not neutralize or incorrectly neutralizes special elements or syntax that can be interpreted as template expressions or other code directives when processed by the engine. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-28228 since 02/25/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1221 according to MITRE ATT&CK.

Upgrading to version 19.1.31, 20.1.18 or 20.2.5 eliminates this vulnerability.

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Productinfo

Name

• OpenOlat

Version

• 19.1.0
• 19.1.1
• 19.1.2
• 19.1.3
• 19.1.4
• 19.1.5
• 19.1.6
• 19.1.7
• 19.1.8
• 19.1.9
• 19.1.10
• 19.1.11
• 19.1.12
• 19.1.13
• 19.1.14
• 19.1.15
• 19.1.16
• 19.1.17
• 19.1.18
• 19.1.19
• 19.1.20
• 19.1.21
• 19.1.22
• 19.1.23
• 19.1.24
• 19.1.25
• 19.1.26
• 19.1.27
• 19.1.28
• 19.1.29
• 19.1.30
• 20.1.0
• 20.1.1
• 20.1.2
• 20.1.3
• 20.1.4
• 20.1.5
• 20.1.6
• 20.1.7
• 20.1.8
• 20.1.9
• 20.1.10
• 20.1.11
• 20.1.12
• 20.1.13
• 20.1.14
• 20.1.15
• 20.1.16
• 20.1.17
• 20.2.0
• 20.2.1
• 20.2.2
• 20.2.3
• 20.2.4

Website

• Product: https://github.com/OpenOLAT/OpenOLAT/

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