CVE
CVE-2026-18691
Improper Authentication in MongoDB Intra-Cluster Connections Allows Credential Exposure
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.
Package Versions Affected
Package Version
patch Availability
No items found.
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CVSS Version
Severity
Base Score
CVSS Version
Score Vector
C
H
U
9
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4.0
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/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:X/V:X/RE:X/U:X
C
H
U
0
-
C
H
U
-
Related Resources
No items found.
References
https://jira.mongodb.org/browse/SERVER-130264, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/18xxx/CVE-2026-18691.json, https://nvd.nist.gov/vuln/detail/CVE-2026-18691