What is CVE-2026-9749?

CVE-2026-9749 is a medium-severity vulnerability in Mongodb, classified under Reachable Assertion. CVSS score: 6.5/10. Published 2026-06-09.

How severe is CVE-2026-9749?

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

Vulnerability in Mongodb

CVE-2026-9749

This issue can occur when running an aggregation pipeline that uses the internal $exchange stage configured with key-range partitioning and order-preserving delivery. If a single key range produces enough documents to fill its exchange buf…

EPSS: 0.003 (18.9th percentile) — read the EPSS interpretation.

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.

Affected products

Mongodb
Mongodb Server — versions 8.3.0, 8.2.0, 8.0.0

Weakness classification (CWE)

CWE-617 — Reachable Assertion

References

cna@mongodb.com (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-9749?: CVE-2026-9749 is a medium-severity vulnerability in Mongodb, classified under Reachable Assertion. CVSS score: 6.5/10. Published 2026-06-09.
How severe is CVE-2026-9749?: Medium severity. CVSS v3 base score is 6.5 out of 10.