CVE-2026-18691
Medium
Elevated severity or exploit probability.
CVSS base
8.8
HIGH
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS — probability of exploitation (30 days)
0.2%
13.9th percentile
CISA KEV
Not listed
Weakness / dates
CWE-757
Published 2026-08-11 · modified 2026-09-16
CVSS breakdown
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
| Attack Vector | A | Adjacent |
| Attack Complexity | L | Low |
| Privileges Required | N | None |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | H | High |
Timeline
- 2026-08-11 — Published (NVD)
- 2026-09-16 — Last modified (NVD)
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.