CVE-2026-21891
CRITICALCVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
Lifecycle Timeline
3Description
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.
Analysis
ZimaOS (fork of CasaOS) through 1.5.0 has an authentication bypass where passwords for system service accounts are not properly validated during login. Attackers can access the system using known service account names with any password. …
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Remediation
Within 24 hours: Identify all affected systems running versions and apply vendor patches immediately. Audit authentication configurations and rotate any potentially compromised credentials.
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