CVE-2026-21891 Details.
ZimaOS - Authentication Bypass
Atlas does not check this one. Needs requests that change data.
To test for this one, the check would have to send requests that could change data on the site. Atlas only ever reads public pages, so it does not run this check.
About CVE-2026-21891. What It Means.
ZimaOS <= 1.5.0 contains a broken authentication caused by improper password validation for known system service accounts in the login function, letting attackers authenticate with any password for these accounts, exploit requires knowledge of common usernames.
Affected Product. What Is Hit.
- Vendor
- zimaspace
- Product
- Zimaspace ZimaOS
FAQ
Common Questions.
ZimaOS - Authentication Bypass. ZimaOS <= 1.5.0 contains a broken authentication caused by improper password validation for known system service accounts in the login function, letting attackers authenticate with any password for these accounts, exploit requires knowledge of common usernames.
No. To test for this one, the check would have to send requests that could change data on the site. Atlas only ever reads public pages, so it does not run this check. The facts about CVE-2026-21891 are on this page, and you can request a demo to see how Brandefense watches your whole external attack surface.
CVE-2026-21891 is not on the CISA Known Exploited Vulnerabilities list at the time of writing, but it is still worth fixing.
Update Zimaspace ZimaOS to the latest version from the vendor, or follow the vendor's advice to switch off the affected feature. Vendor links are listed on this page when they are known.
This page lists the public facts about CVE-2026-21891. Atlas does not run a check for it, so nothing here says whether a particular site is affected.