CVE-2026-18691
Critical
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.
SeverityCritical
CVSS9.0
Exploit probability29. percentile0.4%
Product
Mongodb
PublishedAug 11, 2026
First seenAug 11, 2026
Weakness typeCWE-757CWE-757
How to fix
Update
- mongodb mongodb7.0.40, 8.0.29, 8.3.8 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mongodb mongodb | 7.0.0 ≤ v < 7.0.40, 8.0.0 ≤ v < 8.0.29, 8.2.0 ≤ v ≤ 8.2.12, 8.3.0 ≤ v < 8.3.8, 9.0.0, 9.1.0 | 7.0.40, 8.0.29, 8.3.8 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
In the Intelligence 360 plan
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.