CVE-2026-18691 (GCVE-0-2026-18691)

Vulnerability from cvelistv5 – Published: 2026-08-11 18:46 – Updated: 2026-08-11 20:22
VLAI
Title
Improper Authentication in MongoDB Intra-Cluster Connections Allows Credential Exposure
Summary
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.
Severity
9 (Critical)
CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
8.8 (High)
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-11 20:21 UTC
CWE
  • CWE-757 - Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')
Assigner
mongodb CNA under the mitre root
CNA scorecard C 70/100 over 220 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
MongoDB MongoDB Server Affected: 8.3.0 , < 8.3.8 (semver)
Affected: 8.0 , < 8.0.29 (semver)
Affected: 7.0 , < 7.0.40 (semver)
guessed Create a notification for this product.
Show details on NVD website
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