MongoDB Server up to 7.0.39/8.0.28/8.3.7 Intra-cluster Connection Setup improper authentication

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.0$0-$5k0.40+

Summaryinfo

A vulnerability was found in MongoDB Server up to 7.0.39/8.0.28/8.3.7 and classified as critical. Impacted is an unknown function of the component Intra-cluster Connection Setup. Such manipulation leads to improper authentication. This vulnerability is listed as CVE-2026-18691. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in MongoDB Server up to 7.0.39/8.0.28/8.3.7. It has been rated as critical. Affected by this issue is an unknown code of the component Intra-cluster Connection Setup. The manipulation with an unknown input leads to a improper authentication vulnerability. Using CWE to declare the problem leads to CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. Impacted is confidentiality, integrity, and availability. CVE summarizes:

An issue in MongoDB Server's intra-cluster connection setup could allow a party with suitable network access to influence which authentication mechanism is used when one replica set member connects to another. Under certain conditions, this could cause the cluster's shared internal credential to be transmitted in a less-protected form, potentially allowing that credential to be recovered. If recovered, the credential could be used to authenticate as the internal superuser to nodes in the deployment.

The advisory is shared for download at jira.mongodb.org. This vulnerability is handled as CVE-2026-18691 since 08/03/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available.

Upgrading to version 7.0.40, 8.0.29 or 8.3.8 eliminates this vulnerability.

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Productinfo

Type

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Improper authentication
CWE: CWE-287
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Server 7.0.40/8.0.29/8.3.8

Timelineinfo

08/03/2026 CVE reserved
08/11/2026 +8 days Advisory disclosed
08/11/2026 +0 days VulDB entry created
08/11/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: jira.mongodb.org
Status: Confirmed

CVE: CVE-2026-18691 (🔒)
GCVE (CVE): GCVE-0-2026-18691
GCVE (VulDB): GCVE-100-388448

Entryinfo

Created: 08/11/2026 21:21
Changes: 08/11/2026 21:21 (55)
Complete: 🔍
Cache ID: 216::103

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