IceWhaleTech ZimaOS up to 1.5.0 Login improper authentication

Summaryinfo

A vulnerability labeled as critical has been found in IceWhaleTech ZimaOS up to 1.5.0. This vulnerability affects unknown code of the component Login. Such manipulation leads to improper authentication. This vulnerability is uniquely identified as CVE-2026-21891. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as critical, has been found in IceWhaleTech ZimaOS up to 1.5.0. Affected by this issue is an unknown part of the component Login. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-21891 since 01/05/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 01/08/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• IceWhaleTech

Name

• ZimaOS

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5.0

Website

• Product: https://github.com/IceWhaleTech/ZimaOS/

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