CVE-2021-20147Public exploitNetwork attack vector

Domain user enumeration via ChangePasswordAPI response discrepancy

Published Jan 3, 2022 · Updated Aug 3, 2024

Observable response discrepancy in Zoho ManageEngine ADSelfService Plus before build 6116 allows remote attackers to identify domain users. The ChangePasswordAPI handles UMCP requests for existing and nonexistent login names differently, returning HTTP 200 when the domain user exists. No authentication is required; disclosure is limited to configured domain names and whether submitted Windows domain accounts exist.

CVSS severity5.3
Medium
EPSS probability6.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Observable response discrepancy in Zoho ManageEngine ADSelfService Plus before build 6116 allows remote attackers to identify domain users. The ChangePasswordAPI handles UMCP requests for existing and nonexistent login names differently, returning HTTP 200 when the domain user exists. No authentication is required; disclosure is limited to configured domain names and whether submitted Windows domain accounts exist.

The record

CVE
CVE-2021-20147
Published
Jan 3, 2022
Updated
Aug 3, 2024
Vendor
Zoho Corporation
Product
ManageEngine ADSelfService Plus
Classifications
CWE-203, T1087.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 3, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 6116

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zoho Corporation · ManageEngine ADSelfService Plusversion=< 6116

Published CVSS scores

5.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.3TenableCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.0NIST NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
4.9TenableCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:F/RL:O/RC:C

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-203Observable Discrepancy
T1087.002Domain Account

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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