CVE-2021-40539

Name: CVE-2021-40539
Creator: NVD / NIST
Published: 2021-09-07T17:15:07.367+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10Actively ExploitedEPSS 98.96%

Last modified Jun 17, 2026

CVE-2021-40539 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. Zoho ManageEngine ADSelfService Plus version 6113 and prior is vulnerable to REST API authentication bypass with resultant remote code execution.. CISA has confirmed active exploitation in the wild. EPSS estimates a 98.96% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

98.96%

99.9th percentile

Probability of exploitation in the next 30 days. Learn more

Exploitation Status

This vulnerability is listed in CISA’s Known Exploited Vulnerabilities catalog, confirming active exploitation in the wild. Federal agencies must remediate by Nov 17, 2021.

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Zohocorp	Manageengine Adselfservice Plus	< 6.1
Zohocorp	Manageengine Adselfservice Plus	6.1

References

http://packetstormsecurity.com/files/165085/ManageEngine-ADSelfService-Plus-Authentication-Bypass-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
https://www.manageengine.comProduct
https://www.manageengine.com/products/self-service-password/kb/how-to-fix-authentication-bypass-vulnerability-in-REST-API.htmlPatch, Vendor Advisory
http://packetstormsecurity.com/files/165085/ManageEngine-ADSelfService-Plus-Authentication-Bypass-Code-Execution.htmlExploit, Third Party Advisory, VDB Entry
https://www.manageengine.comProduct
https://www.manageengine.com/products/self-service-password/kb/how-to-fix-authentication-bypass-vulnerability-in-REST-API.htmlPatch, Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40539US Government Resource

Timeline

Published: Sep 7, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-40539?

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

How severe is CVE-2021-40539?

CVE-2021-40539 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 98.96% probability of exploitation in the next 30 days. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

How do I fix CVE-2021-40539?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-40539?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST