What is the CVSS score of CVE-2021-20328?

CVE-2021-20328 has a CVSS 3.1 base score of 6.8 (Medium). CVSS vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N. EPSS exploitation probability: 0.4%.

Is there a patch available for CVE-2021-20328?

Yes, a patch is available for CVE-2021-20328. Update the affected software to the latest version immediately.

Java Driver CVE-2021-20328

MEDIUM

Improper Certificate Validation (CWE-295)

2021-02-25 cna@mongodb.com

Java Information Disclosure Microsoft MongoDB Quarkus Java Driver

6.8

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-295 OWASP Top 10:2025 A07:2025 - Authentication Failures ASVS 5.0 V12 - Secure Communication Certificate validation
Impact	CVSS score of 6.8 (MEDIUM). Attack characteristics: adjacent network attack vector, high complexity, no privileges required, no user interaction not required.
Exploit ScenarioDerived	Successful exploitation could compromise the medium-severity affected system.

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

Patch available 0.4% exploitation probability (EPSS)

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AnalysisAI

Specific versions of the Java driver that support client-side field level encryption (CSFLE) fail to perform correct host name verification on the KMS server’s certificate. Rated medium severity (CVSS 6.8), this vulnerability is no authentication required.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affected Packages

maven org.mongodb:mongo-java-driver fix: 3.11.3, 3.12.8

maven org.mongodb:mongodb-driver fix: 3.11.3, 3.12.8

maven org.mongodb:mongodb-driver-legacy fix: 3.11.3, 3.12.8, 4.0.6, 4.1.2, 4.2.1

maven org.mongodb:mongodb-driver-sync fix: 3.11.3, 3.12.8, 4.0.6, 4.1.2, 4.2.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 4 packages in maven

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 under CWE-295. Specific versions of the Java driver that support client-side field level encryption (CSFLE) fail to perform correct host name verification on the KMS server’s certificate. This vulnerability in combination with a privileged network position active MITM attack could result in interception of traffic between the Java driver and the KMS service rendering Field Level Encryption ineffective. This issue was discovered during internal testing and affects all versions of the Java driver that support CSFLE. The Java async, Scala, and reactive streams drivers are not impacted. This vulnerability does not impact driver traffic payloads with CSFLE-supported key services originating from applications residing inside the AWS, GCP, and Azure network fabrics due to compensating controls in these environments. This issue does not impact driver workloads that don’t use Field Level Encryption. Affected products include: Mongodb Java Driver, Quarkus.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.8 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Adjacent

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

None

DescriptionNVD

Specific versions of the Java driver that support client-side field level encryption (CSFLE) fail to perform correct host name verification on the KMS server’s certificate. This vulnerability in combination with a privileged network position active MITM attack could result in interception of traffic between the Java driver and the KMS service rendering Field Level Encryption ineffective. This issue was discovered during internal testing and affects all versions of the Java driver that support CSFLE. The Java async, Scala, and reactive streams drivers are not impacted. This vulnerability does not impact driver traffic payloads with CSFLE-supported key services originating from applications residing inside the AWS, GCP, and Azure network fabrics due to compensating controls in these environments. This issue does not impact driver workloads that don’t use Field Level Encryption.

Threat Intelligence Overview

EPSS Score

0.4%

Top 65% exploitable

Threat Intel

1 source

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS CISA

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 No

EPSS 0.4%

Patch available Yes

Active threat Yes

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

None

System Exposure· derived

Controlled

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +34

PoC: 0

Weaponized: 0

Threat intel: +10

Gov advisory: 0

Attack Technique

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.