CVE-2026-18703Network attack vectorHinoki check available

Authentication policy bypass via unchecked MONGODB-X509 path

Published Aug 11, 2026 · Updated Aug 11, 2026

Incorrect authorization in MongoDB Server 8.3.0 through 8.3.7 allows remote authenticated users to use a disabled authentication method. The SASL MONGODB-X509 path fails to enforce the configured authenticationMechanisms restriction before accepting a valid client certificate. Exploitation requires a valid client certificate, a corresponding user account, and a configuration that excludes certificate authentication.

CVSS severity2.3
Low
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Incorrect authorization in MongoDB Server 8.3.0 through 8.3.7 allows remote authenticated users to use a disabled authentication method. The SASL MONGODB-X509 path fails to enforce the configured authenticationMechanisms restriction before accepting a valid client certificate. Exploitation requires a valid client certificate, a corresponding user account, and a configuration that excludes certificate authentication.

The record

CVE
CVE-2026-18703
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
MongoDB
Product
MongoDB Server
Classifications
CWE-863, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=8.3.0 <8.3.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

MongoDB · MongoDB Serverversion=8.3.0 <8.3.8

Published CVSS scores

2.3MongoDB, Inc.CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
4.2MongoDB, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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