CVE-2026-54365

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.

CVSS 4.0

8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 30% of CVEs (scores of 2026-10-25)

CWE

CWE-306

Published

2026-07-30

Modified

2026-10-23

Record from

the NVD, synced 2026-10-24

References

• https://www.centrestack.com/
• https://www.vulncheck.com/advisories/centrestack-unauthenticated-user-creation-via-deserialization-in-gsnamespace-dll

Check your stackJSON