---
id: CVE-2026-54365
title: >-
  CentreStack before 17.3 contains an unauthenticated deserialization
  vulnerability in GSNamespace.dll that allows unauthenticated attackers to
  create arbitrary local OS user accounts by supplying a crafted base64-encoded
  XML string to exp…
summary: >-
  CentreStack before 17.3 contains an unauthenticated deserialization
  vulnerability in GSNamespace.dll that allows unauthenticated attackers to
  create arbitrary local OS user accounts by supplying a crafted base64-encoded
  XML string to exp…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-306
published: '2026-07-30'
updated: '2026-07-31'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-54365'
references:
  - url: 'https://www.centrestack.com/'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/centrestack-unauthenticated-user-creation-via-deserialization-in-gsnamespace-dll
    label: disclosure@vulncheck.com
tags:
  - nvd
epss: 0.00372
epssPercentile: 0.28401
ingestedAt: '2026-08-01T22:15:46.001Z'
---

## Overview

CentreStack before 17.3 contains an unauthenticated deserialization vulnerability in GSNamespace.dll that allows unauthenticated attackers to create arbitrary local OS user accounts by supplying a crafted base64-encoded XML string to exposed API endpoints. Attackers can send a malicious StorageConfigure parameter to the jsonimportuserbyupn, jsonimportuserbyupnex, or japiimportuserbyupn endpoints to trigger InternalImportAdUserByUPN(), causing GladinetCloudMonitor.exe to invoke the NetUserAdd Windows API with attacker-controlled credentials and create arbitrary directories on the server filesystem.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.