CVE-2021-40539

highpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.990 · 100 %ileexploit · weaponizedEURUUS

grimoire priorityP0 · Act now

Exploitable?

Yes · in the wild

CISA KEV · 6 exploits · weaponized

Likely / severe?

99.0% (100th) EPSS

CVSS 7.5 · high

Is it mine?

4 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

added 2021-11-03remediate by 2021-11-17

required action Apply updates per vendor instructions.

EPSS · scored 2026-10-23

Zoho ManageEngine ADSelfService Plus Authentication Bypass Vulnerability

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

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 7.5–9.8

v2.07.5highAV:N/AC:L/Au:N/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 10 · impact 6.4

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v3.19.8criticalAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondaryexploitability 3.9 · impact 5.9

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Hsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: active · Automatable: yes · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-706USprimaryCWE-287US

ATT&CK techniques

ATT&CK techniques this enables or maps to.

exploits (6)

Public proof-of-concept and weaponised exploit code.

exploit/windows/http/manageengine_adselfservice_plus_cve_2021_40539ManageEngine ADSelfService Plus CVE-2021-40539weaponized · metasploit
Bu0uCat/ADSelfService-Plus-RCE-CVE-2021-40539ADSelfService Plus RCE漏洞检测工具 (二开)PoC · poc_in_github
DarkSprings/CVE-2021-40539CVE-2021-40539 POCPoC · poc_in_github
lpyydxs/CVE-2021-40539CVE-2021-40539：ADSelfService Plus RCE漏洞PoC · poc_in_github
lpyzds/CVE-2021-40539CVE-2021-40539：ADSelfService Plus RCE漏洞PoC · poc_in_github
synacktiv/CVE-2021-40539Exploitation code for CVE-2021-40539PoC · poc_in_github

affected products (4)

Products and version ranges known to be affected.

n/a n/a≤ n/aenisa_euvdEU
ZOHO Corp. ManageEngine ADSelfService Plus≤ 6114fstec_bduRU
zohocorp manageengine adselfservice plus< 6.1nvdUScpe:2.3:a:zohocorp:manageengine_adselfservice_plus:*:*:*:*:*:*:*:*
zohocorp manageengine adselfservice plus= 6.1nvdUScpe:2.3:a:zohocorp:manageengine_adselfservice_plus:*:*:*:*:*:*:*:*

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd NVD CVE.org MITRE

published 2021-09-07modified 2026-06-17

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+185 more

references (13)

External citations — patches, advisories, analysis.

scry

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