Vulnerability Description
ZimaOS is a fork of CasaOS, an operating system for Zima devices and x86-64 systems with UEFI. In versions up to and including 1.5.0, the application checks the validity of the username but appears to skip, misinterpret, or incorrectly validate the password when the provided username matches a known system service account. The application's login function fails to properly handle the password validation result for these users, effectively granting authenticated access to anyone who knows one of these common usernames and provides any password. As of time of publication, no known patched versions are available.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Zimaspace | Zimaos | <= 1.5.0 |
Related Weaknesses (CWE)
References
- https://github.com/IceWhaleTech/ZimaOS/security/advisories/GHSA-xj93-qw9p-jxq4ExploitVendor Advisory
- https://github.com/IceWhaleTech/ZimaOS/security/advisories/GHSA-xj93-qw9p-jxq4ExploitVendor Advisory
FAQ
What is CVE-2026-21891?
CVE-2026-21891 is a vulnerability with a CVSS score of 9.4 (CRITICAL). ZimaOS is a fork of CasaOS, an operating system for Zima devices and x86-64 systems with UEFI. In versions up to and including 1.5.0, the application checks the validity of the username but appears to...
How severe is CVE-2026-21891?
CVE-2026-21891 has been rated CRITICAL with a CVSS base score of 9.4/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-21891?
Check the references section above for vendor advisories and patch information. Affected products include: Zimaspace Zimaos.