What is the CVSS score of CVE-2021-37420?

CVE-2021-37420 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N. EPSS exploitation probability: 1.9%.

Is there a public PoC exploit available for CVE-2021-37420?

Yes, a public proof-of-concept exploit is available for CVE-2021-37420. Prioritise patching immediately. EPSS: 1.9%.

Is there a patch available for CVE-2021-37420?

Yes, a patch is available for CVE-2021-37420. Update the affected software to the latest version immediately.

Zoho CVE-2021-37420

MEDIUM

Missing Authentication for Critical Function (CWE-306)

2021-09-21 cve@mitre.org

Authentication Bypass Zoho Manageengine Admanager Plus Zohocorp

6.5

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-306 OWASP Top 10:2025 A07:2025 - Authentication Failures ASVS 5.0 V6 - Authentication Authentication required for critical functions MITRE ATT&CK 1 technique across 1 tactic: Initial Access The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 6.5 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	A remote attacker could access critical functionality without authentication by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 1.9% exploitation probability (EPSS)

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AnalysisAI

Zoho ManageEngine ADSelfService Plus before 6112 is vulnerable to mail spoofing. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Require authentication for all sensitive operations, implement defense in depth.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Missing Authentication for Critical Function (CWE-306), which allows attackers to access critical functionality without authentication. Zoho ManageEngine ADSelfService Plus before 6112 is vulnerable to mail spoofing. Affected products include: Zohocorp Manageengine Admanager Plus. Version information: before 6112.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.5 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

DescriptionNVD

Zoho ManageEngine ADSelfService Plus before 6112 is vulnerable to mail spoofing.

Threat Intelligence Overview

EPSS Score

1.9%

Top 23% exploitable

Exploit

POC

Public exploit code exists

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC Yes

EPSS 1.9%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +2

CVSS: +32

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Authentication Bypass CRITICAL

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)NVD

cpe:2.3:a:zohocorp:manageengine_admanager_plus:*:*:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:-:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6100:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6101:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6102:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6103:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6104:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6105:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6106:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6107:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6108:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6109:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6110:*:*:*:*:*:*

cpe:2.3:a:zohocorp:manageengine_admanager_plus:6.1:6111:*:*:*:*:*:*

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Same weakness CWE-306 – Missing Authentication for Critical Function

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References

Advisories & patches

PATCH https://pitstop.manageengine.com/portal/en/community/topic/adselfservice-plus-6112-hotfix-release ADVISORY https://www.manageengine.com

Search Externally

GitHub PoC

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