CVE-2026-21891

critical · 9.4

A public exploit / detection template exists

Weaponised detection is publicly available, which meaningfully raises real-world risk regardless of CVSS. nuclei-templates →

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.

9.4

CVSS

2.4%

EPSS (exploit prob.)

83rd

EPSS percentile

2026-01-08

Published

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L

Weaknesses

CWE-287

Affected products

Vendor	Product	Affected versions
zimaspace	zimaos	<= 1.5.0

Check a specific version with /api/v1/cve/match.

References

Query this programmatically:

curl https://evil-db.io/api/v1/cve/CVE-2026-21891