Hard-Coded Key Used For Remember-me Token in Opencast
Impact
The security configuration in etc/security/mh_default_org.xml enables a remember-me cookie based on a hash created from the username, password, and an additional system key. Opencast has hard-coded this system key in the large XML file and never mentions to change this, basically ensuring that all systems use the same key:
<sec:remember-me key="opencast" user-service-ref="userDetailsService" />This means that an attacker getting access to a remember-me token for one server can get access to all servers which allow log-in using the same credentials without ever needing the credentials. For example, a remember-me token obtained from develop.opencast.org can be used on stable.opencast.org without actually knowing the log-in credentials.
Such an attack will usually not work on different installations – assuming that safe, unique passwords are used – but it is basically guaranteed to work to get access to all machines of one cluster if a token from one machine is compromised.
Patches
This problem is fixed in Opencast 7.6 and Opencast 8.1
Workarounds
We strongly recommend updating to the patched version. Still, as a workaround for older versions, in etc/security/mh_default_org.xml, set a custom key for each server:
<sec:remember-me key="CUSTOM_RANDOM_KEY" user-service-ref="userDetailsService" />References
- Relevant lines in the security configuration
- Spring Security Remember-Me Authentication Documentation
For more information
If you have any questions or comments about this advisory:
- Open an issue in opencast/opencast
- For security-relevant information, email us at security@opencast.org
Thanks
Thanks to @LukasKalbertodt for reporting the issue.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.opencastproject:opencast-kernel | < 7.6, >= 8.0, < 8.1 | 7.6, 8.1 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N- Weakness (CWE)
CWE-798- Platform
- Java / Kotlin (Maven)
- Package
org.opencastproject:opencast-kernel- Disclosed
- 30.01.2020
- Updated
- 11.10.2026 13:19
Sources and licenses
OSV / GitHub Advisory Database - GHSA-mh8g-hprg-8363 - CC BY 4.0
Vulnerability history: org.opencastproject:opencast-kernel
All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 7
- First → latest
- 01.2020 07.2025
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 1
- High 2
- Medium 4
Disclosures per year
- 2020: 4
- 2021: 1
- 2022: 1
- 2023: 0
- 2024: 0
- 2025: 1
- 2026: 0
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