CVE-2026-18691

published 2026-08-11

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…

Priority P3 52 high 8.8 CVSS 3.1

AV A AC L PR N UI N S U C H I H A H

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.

Affected

10 ranges

Vendor	Product	Version range	Fixed in
mongodb	mongodb	—	—
mongodb	mongodb	—	—
mongodb	mongodb	—	—
mongodb	mongodb	>= 7.0.0 < 7.0.40	7.0.40
mongodb	mongodb	>= 8.0.0 < 8.0.29	8.0.29
mongodb	mongodb	8.2.0 – 8.2.12	—
mongodb	mongodb	>= 8.3.0 < 8.3.8	8.3.8
mongodb	mongodb_server	>= 7.0 < 7.0.40	7.0.40
mongodb	mongodb_server	>= 8.0 < 8.0.29	8.0.29
mongodb	mongodb_server	>= 8.3.0 < 8.3.8	8.3.8

CVSS provenance

nvd v3.1 8.8 HIGH CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd v4.0 9.0 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/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

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CWE-757