CVE-2026-28286

HighPublic PoC

Published: 02 March 2026

Published

02 March 2026

Modified

05 March 2026

KEV Added

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Patch

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CVSS Score 8.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

EPSS Score 0.0009 25.6th percentile

Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-28286 is a high-severity External Control of File Name or Path (CWE-73) vulnerability in Zimaspace Zimaos. Its CVSS base score is 8.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 25.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and SI-10 (Information Input Validation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Privilege Escalation (T1068) and 5 other techniques. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-10 Information Input Validation good match

prevent

Directly addresses the API's failure to validate target paths in crafted requests, preventing unauthorized file creation in sensitive directories like /etc or /usr.

AC-3 Access Enforcement good match

prevent

Enforces logical access controls to system resources, mitigating the bypass of frontend restrictions by requiring the API to validate and restrict writes to critical paths.

AC-6 Least Privilege partial match

prevent

Limits low-privileged users' access via the API to only necessary privileges, reducing the impact of path validation bypasses on sensitive system directories.

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

T1136.001 Local Account Persistence

Adversaries may create a local account to maintain access to victim systems.

attack.mitre.org →

T1053.003 Cron Execution

Adversaries may abuse the <code>cron</code> utility to perform task scheduling for initial or recurring execution of malicious code.

attack.mitre.org →

T1543.002 Systemd Service Persistence

Adversaries may create or modify systemd services to repeatedly execute malicious payloads as part of persistence.

attack.mitre.org →

T1037.004 RC Scripts Persistence

Adversaries may establish persistence by modifying RC scripts, which are executed during a Unix-like system’s startup.

attack.mitre.org →

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

Path validation bypass enables unauthorized file/directory creation in /etc and /usr, directly facilitating Linux persistence mechanisms (systemd services, cron, rc scripts, local accounts) and privilege escalation via T1068; exploitation occurs through the public-facing API (T1190).

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

NVD Description

ZimaOS is a fork of CasaOS, an operating system for Zima devices and x86-64 systems with UEFI. In version 1.5.2-beta3, the application enforces restrictions in the frontend/UI to prevent users from creating files or folders in internal OS paths. However,…

when interacting directly with the API, the restrictions are bypass-able. By sending a crafted request targeting paths like /etc, /usr, or other sensitive system directories, the API successfully creates files or directories in locations where normal users should have no write access. This indicates that the API does not properly validate the target path, allowing unauthorized operations on critical system directories. No known patch is publicly available.

Deeper analysisAI

CVE-2026-28286 is a path validation vulnerability in ZimaOS version 1.5.2-beta3, a fork of CasaOS designed as an operating system for Zima devices and x86-64 systems with UEFI. The frontend UI enforces restrictions to prevent users from creating files or folders in internal OS paths, but the backend API lacks proper validation of target paths. This allows attackers to bypass restrictions by sending crafted requests that target sensitive system directories such as /etc or /usr, enabling unauthorized file or directory creation in locations inaccessible to normal users. The vulnerability is rated 8.5 on the CVSS 3.1 scale (AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H) and maps to CWE-73 (External Control of File Name or Path).

A low-privileged authenticated user (PR:L) can exploit this over the network (AV:N) with high attack complexity (AC:H) and no user interaction (UI:N), achieving scope change (S:C) for high confidentiality, integrity, and availability impacts (C:I:A:H). By crafting API requests to specify restricted paths, the attacker can write files or create directories in critical system areas, potentially leading to privilege escalation, persistence, or full system compromise depending on the content written.

The GitHub Security Advisory at https://github.com/IceWhaleTech/ZimaOS/security/advisories/GHSA-65mg-9gw5-vr7g details the issue, confirming the API bypass in version 1.5.2-beta3. No patch is publicly available, so practitioners should restrict API access, monitor for anomalous file creations in sensitive directories, and consider isolating ZimaOS instances until a fix is released.