CVE-2026-54365: CentreStack < 17.3 Unauthenticated User Creation via Deserialization in GSNamespace.dll

Severity: high (CVSS 7.5 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: none known
Published: 2026-07-30 · updated 2026-10-23
Weakness: CWE-306

Description

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.

Affected products

Gladinet CentreStack: before 17.3 — fixed in 17.3

How to fix

Upgrade to a fixed version: Gladinet CentreStack 17.3. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-54365 or the next vulnerability affects your stack