Vulnerability record

CVE-2026-21891

A permanent, source-backed tracker page. Values are shown only when returned; explicit gaps and read failures remain different states.

Full record read. Reported values and explicit gaps below come from the tracked record. Tracker snapshot: Aug 8, 2026.

What it is

Reported

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.… Source description excerpt; complete tracked detail loads below.

NVD published: Jan 8, 2026 · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026

What is affected

Reported

zimaspace — zimaos. Product-level identification only; no affected-version conclusion is available from this field.

NVD published: Jan 8, 2026 · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026

Urgency and basis

Reported

Act · 453.5

Tracker decision tier from the evidence detailed below · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026

Exploitation evidence

Reported

kev-listed · VulnCheck KEV

VulnCheck KEV added: Mar 7, 2026 · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026

What to do

Reported

Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

Source remediation ↗

Tracked source remediation field · Source record updated: Aug 8, 2026 · Tracker snapshot: Aug 8, 2026

Evidence detail

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