CVE-2026-18691CWE-757

CVE-2026-18691

High · published August 11, 2026

CVSS v3.1
8.8
EPSS
0%
Percentile
28.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
8.8 · HIGH
Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00355 · 28.0th percentile
Weakness
CWE-757 · Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')
Published
2026-08-11T23:17Z
Affected products (7)
ProductVersionsFixed in
mongodb/mongodb≥ 7.0.0, < 7.0.407.0.40
mongodb/mongodb≥ 8.0.0, < 8.0.298.0.29
mongodb/mongodb≥ 8.2.0, ≤ 8.2.12—
mongodb/mongodb≥ 8.3.0, < 8.3.88.3.8
mongodb/mongodball versions—
mongodb/mongodball versions—
mongodb/mongodball versions—
References (1)
EPSS history
Timeline
  • 11 AUG 18:46Z
    Improper Authentication in MongoDB Intra-Cluster Connections Allows Credential Exposure
    cvelistv5