What is CVE-2018-20803?

CVE-2018-20803 is a medium-severity vulnerability in MongoDB, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2020-11-23.

How severe is CVE-2018-20803?

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

Vulnerability in MongoDB

CVE-2018-20803

A user authorized to perform database queries may trigger denial of service by issuing specially crafted queries, which loop indefinitely in mathematics processing while retaining locks. This issue affects MongoDB Server v4.0 versions prior to 4.0.5; MongoDB Server v3.6 versions prior to 3.6.10 and MongoDB Server v3.4 versions prior to 3.4.19.

Published 2020-11-23 · last modified 2026-06-17.

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: 0.014 (72.1th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 72nd percentile — 72.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.013 · newest: 0.014 · change: +0.002

Affected products

MongoDB
MongoDB Inc. Server — versions 4.0, 3.6, 3.4

Weakness classification (CWE)

CWE-835 — Loop with Unreachable Exit Condition (Infinite Loop)

References

jira.mongodb.org/browse/SERVER-38070 (Patch, Issue Tracking, Vendor Advisory)

Frequently asked questions

What is CVE-2018-20803?: CVE-2018-20803 is a medium-severity vulnerability in MongoDB, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 6.5/10. Published 2020-11-23.
How severe is CVE-2018-20803?: Medium severity. CVSS v3 base score is 6.5 out of 10.