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

Severity: critical (CVSS 10.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-03 · updated 2026-07-24
Weakness: CWE-918

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.

Affected products

IceWhaleTech ZimaOS: before 1.5.3 — fixed in 1.5.3

How to fix

Upgrade to a fixed version: IceWhaleTech ZimaOS 1.5.3. Check the vendor advisory for mitigations.

References

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