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High 8.8Published Aug 11, 2026

CVE-2026-18691Improper Authentication in MongoDB Intra-Cluster Connections Allows Credential Exposure

Updated under an hour ago ()

Does this affect you?

It affects MongoDB Server and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-757
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
mongodb
NVD analysis
Analyzed
Record last updated
Aug 11, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
MongoDB MongoDB Server
mongodb:server (from the name)
from 8.3.0 before 8.3.8; from 8.0 before 8.0.29; from 7.0 before 7.0.40
CNA record
mongodb mongodb
mongodb:mongodb
from 7.0.0 before 7.0.40; from 8.0.0 before 8.0.29; from 8.2.0 through 8.2.12; from 8.3.0 before 8.3.8; 9.0.0; 9.0.0; 9.1.0
NVD

References

  • vendor-advisory, issue-tracking

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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