What is CVE-2026-9747?

CVE-2026-9747 is a medium-severity vulnerability in MongoDB, classified under Reachable Assertion. CVSS score: 6.5/10. Published 2026-06-09.

How severe is CVE-2026-9747?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in MongoDB

CVE-2026-9747

Adding fromRouter:true and runtimeConstants.userRoles could cause aggregations to crash mongodb server.

Published 2026-06-09 · last modified 2026-07-23.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (38.3th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 38th percentile — 38.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

MongoDB
MongoDB Server — versions 8.3.0, 8.2.0, 8.0.0

Weakness classification (CWE)

CWE-617 — Reachable Assertion

References

jira.mongodb.org/browse/SERVER-123918 (Vendor Advisory)

Frequently asked questions

What is CVE-2026-9747?: CVE-2026-9747 is a medium-severity vulnerability in MongoDB, classified under Reachable Assertion. CVSS score: 6.5/10. Published 2026-06-09.
How severe is CVE-2026-9747?: Medium severity. CVSS v3 base score is 6.5 out of 10.