Improper Enforcement of Authentication Mechanism Restrictions in MongoDB Server Allows Use of Disabled Authentication Method (CVE-2026-18703) | HOL Guard CVE

Medium · CVSS 4.2CVE-2026-18703

Improper Enforcement of Authentication Mechanism Restrictions in MongoDB Server Allows Use of Disabled Authentication Method

Answer in brief

CVE-2026-18703 records a Medium severity (CVSS 4.2) vulnerability in Improper Enforcement of Authentication Mechanism Restrictions in MongoDB Server Allows Use of Disabled Authentication Method. The current sources do not mark it as known exploited. The current feed maps MongoDB/MongoDB Server (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 11, 2026Updated Sep 16, 2026Source checked Sep 25, 2026First seen by HOL Aug 11, 2026Material review Sep 16, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 4.2
Exploitation: Not marked as known exploited
Affected software: 5 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 4.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps MongoDB/MongoDB Server (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
Product	Affected versions	Fixed versions
cpe:2.3:a:mongodb:mongodb::::::::	Not reported	Not reported
cpe:2.3:a:mongodb:mongodb:9.0.0:alpha0:::-:-::	Not reported	Not reported
cpe:2.3:a:mongodb:mongodb:9.0.0:alpha1:::-:-::	Not reported	Not reported
cpe:2.3:a:mongodb:mongodb:9.1.0:alpha0:::-:-::	Not reported	Not reported

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
MongoDB/MongoDB Servergeneric	>=8.3.0 <8.3.8	8.3.8

Recommended response

Check inventory. Check lockfiles and deployed manifests for MongoDB/MongoDB Server.
Review the reported fix. Update MongoDB/MongoDB Server to 8.3.8 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 16, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 11, 2026

Sources and claim methodology

Source referencejira.mongodb.org

Upstream source description

An issue in MongoDB Server could allow a party with a valid client certificate and a corresponding user account to authenticate using a certificate-based authentication method, even when an administrator has configured the server to restrict authentication to other mechanisms. This could allow authentication through a method the administrator intended to disable.

Quoted source text, attributed separately from HOL analysis.