CVE-2026-81518: CWE-295: Improper Certificate Validation in MongoDB BI Connector
Description
CVE-2026-81518 is a high-severity vulnerability in the MongoDB BI Connector where improper certificate validation occurs. Specifically, when mongosqld is configured with a client certificate authority file, it requests but does not require a client certificate during the TLS handshake. This allows clients without certificates to connect. In environments relying solely on client certificates for user identification, this flaw enables unauthorized remote parties with network access to read MongoDB data exposed through the connector.
CVSS v4.0
Score 8.7high
Affected software
MongoDB
BI Connector
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The MongoDB BI Connector's mongosqld component, when configured to use a client certificate authority file, requests client certificates during TLS handshakes but does not enforce their presence. This improper certificate validation (CWE-295) means that clients presenting no certificate can still establish a session. Consequently, in deployments that depend exclusively on client certificates for authentication, an attacker with network access can bypass authentication controls and access data exposed by the BI Connector.
Potential Impact
An attacker with network access to the MongoDB BI Connector listener can establish a session without presenting a client certificate, bypassing authentication mechanisms that rely solely on client certificates. This unauthorized access allows reading of MongoDB data exposed through the connector, potentially leading to data disclosure.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, avoid relying solely on client certificates for authentication with the BI Connector or restrict network access to the connector listener to trusted parties only.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mongodb
- Date Reserved
- 2026-08-26T22:07:10.996Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a9206c9acd9273b4963cf5d
Added to database: 08/28/2026, 22:08:09 UTC
Last enriched: 09/07/2026, 15:28:10 UTC
Last updated: 10/13/2026, 18:48:24 UTC
Views: 66
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