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Vulnerability record · CVE-2026-81518 · published 28 August 2026

CVE-2026-81518: Improper certificate validation vulnerability

When mongosqld is configured with a client certificate authority file, the listener requests a client certificate during the TLS handshake but does not require one, so a client that presents no certificate is still accepted. In deployments that rely on client certificates as the sole means of identifying users, a remote party with network access to the listener can therefore establish a session and read the MongoDB data exposed through the connector.

8.7 CVSS 4.0 High EPSS 0.25% · top 84.8% CWE-295 · Improper certificate validation Undergoing Analysis
8.7CVSS 4.0 base score
0.25%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
1References
1 Sep 2026Last modified by NVD

Description

When mongosqld is configured with a client certificate authority file, the listener requests a client certificate during the TLS handshake but does not require one, so a client that presents no certificate is still accepted. In deployments that rely on client certificates as the sole means of identifying users, a remote party with network access to the listener can therefore establish a session and read the MongoDB data exposed through the connector.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

LinkTags
https://www.mongodb.com/docs/bi-connector/current/release-notes/

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Source: NIST National Vulnerability Database (record CVE-2026-81518), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.