CVE-2026-21891: critical vulnerability in IceWhaleTech ZimaOS
ZimaOS has Authentication Bypass via System-Level Username
Published
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65Vexday Risk Score
Patch now. It exploitation observed by VulnCheck and has a working public exploit.
ssvc Actcvss 9.4epss 2.3%
from disclosure to weapon
Published on NVDJan 8
VulnCheck+58d
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:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
Affected products
IceWhaleTech · ZimaOSRelated CVEs — IceWhaleTech ZimaOS
In the same product, most dangerous first.
CVE-2024-49357HIGHZimaOS (Installed Applications and System Information) has Unauthorized Sensitive Data LeakEPSS 23.7%CVE-2024-49359HIGHZimaOS vulnerable to Directory Listing via Parameter ManipulationEPSS 1.0%CVE-2024-48931HIGHZimaOS Arbitrary File Read via Parameter ManipulationEPSS 0.7%CVE-2024-48932MEDIUMZimaOS Unauthenticated API Discloses UsernamesEPSS 0.5%CVE-2024-49358MEDIUMZimaOS vulnerable to Username Enumeration via API ResponsesEPSS 0.5%CVE-2026-28286HIGHZimaOS: Unauthorized Creation of Files/Folders in Restricted System Directories via APIEPSS 0.5%