CVE-2021-40539

CRITICALNVD 9.89.8—Trending — 4 sources updated this weekExploited in the wild

9.8

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

CVSS v3: 9.8
EG Score: 9.8(high)
EPSS: 100.0%
KEV: ⚠ Exploited

Published

September 7, 2021

Last Modified

November 5, 2025

References (7)

cve@mitrehttp://packetstormsecurity.com/files/165085/ManageEngine-ADSelfService-Plus-Authentication-Bypass-Code-Execution.html
cve@mitrehttps://www.manageengine.com
cve@mitrehttps://www.manageengine.com/products/self-service-password/kb/how-to-fix-authentication-bypass-vulnerability-in-REST-API.html
af854a3a-2127-422b-91ae-364da2661108http://packetstormsecurity.com/files/165085/ManageEngine-ADSelfService-Plus-Authentication-Bypass-Code-Execution.html
af854a3a-2127-422b-91ae-364da2661108https://www.manageengine.com
af854a3a-2127-422b-91ae-364da2661108https://www.manageengine.com/products/self-service-password/kb/how-to-fix-authentication-bypass-vulnerability-in-REST-API.html
134c704f-9b21-4f2e-91b3-4a467353bcc0https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40539

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 10× in last 7d / 10× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-05-31 23:55 UTCEG score recompute
2026-05-31 23:55 UTCGHSA enrichment
2026-05-29 22:20 UTCkev_newly_listed
2026-05-27 20:35 UTCkev_newly_listed
2026-05-26 19:13 UTCkev_newly_listed
2026-05-26 10:57 UTCEG score recompute
2026-05-26 10:57 UTCGHSA enrichment
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Publicly available exploits

(5 references)

Working exploit code is in the public domain (1 Metasploit module) (3 GitHub PoCs). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

GitHub PoCBu0uCat/ADSelfService-Plus-RCE-CVE-2021-40539
First seen Oct 16, 2024
ADSelfService Plus RCE漏洞检测工具 (二开)
Open source ↗
GitHub PoCsynacktiv/CVE-2021-40539
First seen Nov 3, 2021
Exploitation code for CVE-2021-40539
Open source ↗
GitHub PoCDarkSprings/CVE-2021-40539
First seen Sep 17, 2021
CVE-2021-40539 POC
Open source ↗
Metasploitexploit/windows/http/manageengine_adselfservice_plus_cve_2021_40539✓ verified
First seen Sep 7, 2021
ManageEngine ADSelfService Plus CVE-2021-40539
Open source ↗
Nucleihttp/cves/2021/CVE-2021-40539.yaml
First seen Jan 1, 2021
Zoho ManageEngine ADSelfService Plus v6113 - Unauthenticated Remote Command Execution
Open source ↗

Frequently asked(6)

What is CVE-2021-40539?

CVE-2021-40539 is a critical vulnerability published on September 7, 2021. Zoho ManageEngine ADSelfService Plus version 6113 and prior is vulnerable to REST API authentication bypass with resultant remote code execution.

When was CVE-2021-40539 disclosed?

CVE-2021-40539 was first published in the National Vulnerability Database on September 7, 2021, with the most recent update on November 5, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-40539 actively exploited?

Yes. CISA added CVE-2021-40539 to the Known Exploited Vulnerabilities catalog on November 3, 2021, affecting Zoho ManageEngine. KEV listing indicates confirmed exploitation in the wild; this CVE warrants immediate patching attention.

What is the CVSS score of CVE-2021-40539?

CVE-2021-40539 has a CVSS v3 base score of 9.8 (NVD).

Which products are affected by CVE-2021-40539?

CVE-2021-40539 affects Zoho ManageEngine. The full affected-products list, including version ranges and fixed versions, is shown in the Affected Packages section of this page.

How do I remediate CVE-2021-40539?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-40539, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-40539

Explore →

Is Your Infrastructure Affected by CVE-2021-40539?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs

CVE-2021-40539

📅 Published

🔄 Last Modified

🔗 References (7)

Weakness Classification(2)

Data Freshness Timeline

Publicly available exploits

❓ Frequently asked(6)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-40539?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (7)

Frequently asked(6)

Related CVEs(same CWE)