VULNERABILITY INTELLIGENCE

CVE-2026-18691

CVSS score9 CRITICAL
EPSS probability0.36%
CISA KEVNot currently listed
Published2026-08-11
Last modified2026-10-23
CVSS vectorCVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

Description

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.

Weakness classification

  • CWE-757: Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')

Primary references