What is CVE-2026-18691?

CVE-2026-18691 is a high-severity vulnerability in Mongodb Server, classified under CWE-757. CVSS score: 8.8/10. Published 2026-08-11.

How severe is CVE-2026-18691?

High severity. CVSS v3 base score is 8.8 out of 10.

Vulnerability in Mongodb Server

CVE-2026-18691

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, thi…

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Mongodb Server — versions 8.3.0, 8.0, 7.0

Weakness classification (CWE)

CWE-757

References

cna@mongodb.com

Frequently asked questions

What is CVE-2026-18691?: CVE-2026-18691 is a high-severity vulnerability in Mongodb Server, classified under CWE-757. CVSS score: 8.8/10. Published 2026-08-11.
How severe is CVE-2026-18691?: High severity. CVSS v3 base score is 8.8 out of 10.