CVE-2026-21891
ZimaOS is a fork of CasaOS, an operating system for Zima devices and x86-64 systems with UEFI.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (2.37%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 2.37% probability · 83th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-287
- Affected
- zimaspace/zimaos
- Source
- security-advisories@github.com
References
- https://github.com/IceWhaleTech/ZimaOS/security/advisories/GHSA-xj93-qw9p-jxq4Exploit, Vendor Advisory
- https://github.com/IceWhaleTech/ZimaOS/security/advisories/GHSA-xj93-qw9p-jxq4Exploit, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.