CVE-2026-28798 Arbitrary internal service access via /v1/sys/proxy when Cloudflare Tunnel is enabled on ZimaOS

Critical 9.1 Published 3 Apr 2026 Updated 6 Apr 2026

Attackers can access internal localhost services via a proxy endpoint when Cloudflare Tunnel is enabled, exposing sensitive data.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-28798?

CVE-2026-28798 is a critical server-side request forgery vulnerability in IceWhaleTech ZimaOS, published on 3 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

ZimaOS is a fork of CasaOS, an operating system for Zima devices and x86-64 systems with UEFI. Prior to version 1.5.3, a proxy endpoint (/v1/sys/proxy) exposed by ZimaOS's web interface can be abused (via an externally reachable domain using a Cloudflare Tunnel) to make requests to internal localhost services. This results in unauthenticated access to internal-only endpoints and sensitive local services when the product is reachable from the Internet through a Cloudflare Tunnel. This issue has been patched in version 1.5.3.

Weakness: CWE-918

Which versions are affected by CVE-2026-28798?

It affects 1 product.

Products include Zimaspace Zimaos.

How do I fix CVE-2026-28798?

No fix has been published for CVE-2026-28798 yet. Limit exposure of the affected software until one is available.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-28798 being exploited?

There is no known exploitation of CVE-2026-28798 in the wild and no public exploit code.

Sources

Also known as GHSA-vqqj-f979-8c8m.