How severe is CVE-2026-28798?

CVE-2026-28798 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-28798 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-28798?

CVE-2026-28798 affects Zimaspace Zimaos. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-28798?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-28798 have an EU (EUVD) identifier?

Yes. CVE-2026-28798 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18843.

When was CVE-2026-28798 published?

CVE-2026-28798 was published on 2026-04-03 and last updated on 2026-06-17.

CVE-2026-28798

CVE-2026-28798 is a critical-severity vulnerability in Zimaspace Zimaos with a CVSS 3.x base score of 9.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-918.

Key facts

Severity: Critical (CVSS 3.x base score 9.0)
EPSS exploit prediction: 0% (31st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-18843
Weakness: CWE-918
Affected product: Zimaspace Zimaos
Published: 2026-04-03
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-28798?: 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.
How severe is CVE-2026-28798?: CVE-2026-28798 has a CVSS 3.x base score of 9.0, rated critical severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-28798 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-28798?: CVE-2026-28798 affects Zimaspace Zimaos. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-28798?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-28798 have an EU (EUVD) identifier?: Yes. CVE-2026-28798 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-18843.
When was CVE-2026-28798 published?: CVE-2026-28798 was published on 2026-04-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:zimaspace:zimaos:*:*:*:*:*:*:*:*

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