CVE-2021-40539: Zoho ManageEngine ADSelfService Plus Authentication Bypass Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2021-11-03. EPSS: 99% chance of exploitation in the next 30 days.

Zoho ManageEngine ADSelfService Plus version 6113 and prior is vulnerable to REST API authentication bypass with resultant remote code execution.

Affected products

• Zohocorp ManageEngine Adselfservice Plus: before 6.1 (fixed in 6.1); version 6.1 only

Published 2021-09-07. Last modified 2026-06-17.