Reference page — cumulative record through Sunday, October 4, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-40539

CVE-2021-40539CRITICAL

n/a n/a — Zoho ManageEngine

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  H  H    9.8   .9896   99.9   YES

AFFECTED
  Product  Versions  Fixed
  n/a      n/a –     —

TIMELINE
  Sep 6   Reserved by mitre
  Sep 7   Published (CNA: mitre)
  Nov 3   Added to CISA KEV, remediation due 2021-11-17

CWE-706 · CNA: mitre · CVSS v3.1 · 4 references · KEV due November 17, 2021

Description

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

Lifecycle

Complete event history — 3 events, chronological
Date	Event	Detail
September 6, 2021	Reserved	Reserved by mitre
September 7, 2021	Published	Published (CNA: mitre)
November 3, 2021	KEV ADDED	Added to CISA KEV, remediation due 2021-11-17

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	n/a	—	n/a	—

Weaknesses

CWE-706

References (4)

http://packetstormsecurity.com/files/165085/ManageEngine-ADSelfService-Plus-Authentication-Bypass-Code-Execution.html [x_refsource_MISC]
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40539 [government-resource]
https://www.manageengine.com [x_refsource_MISC]
https://www.manageengine.com/products/self-service-password/kb/how-to-fix-authentication-bypass-vulnerability-in-REST-API.html [x_refsource_MISC]

Authoritative record: CVE-2021-40539 at cve.org

Weaknesses: CWE-706

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-40539 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Sunday, October 4, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.