CVE-2026-18691
Improper Authentication in MongoDB Intra-Cluster Connections Allows Credential Exposure
CVSS Score
8.8
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-757 |
| Vendor | mongodb |
| Product | mongodb server |
| Ecosystems | |
| Industries | Technology |
| Published | Aug 11, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Attack Vector
Adjacent
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
MongoDB / MongoDB Server
8.3.0 < 8.3.8 8.0 < 8.0.29 7.0 < 7.0.40