What is CVE-2019-2391?

CVE-2019-2391 is a medium-severity vulnerability in MongoDB Js-Bson, classified under Deserialization of Untrusted Data. CVSS score: 4.2/10. Published 2020-03-31.

How severe is CVE-2019-2391?

Medium severity. CVSS v3 base score is 4.2 out of 10.

Is CVE-2019-2391 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Deserialization in MongoDB Js-Bson

CVE-2019-2391

Incorrect parsing of certain JSON input may result in js-bson not correctly serializing BSON. This may cause unexpected application behaviour including data disclosure. This issue affects: MongoDB Inc. js-bson library version 1.1.3 and prior to.

Vulnerability class: Insecure Deserialization

Published 2020-03-31 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.2 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.008 (53.9th percentile), scored 2026-10-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 53.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.008 · change: -0.001

Affected products

MongoDB Js-Bson
MongoDB Inc. Js-Bson — versions 1.0

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

Public proof-of-concept exploits

References

github.com/mongodb/js-bson/releases/tag/v1.1.4 (Patch, Third Party Advisory, Release Notes)

Frequently asked questions

What is CVE-2019-2391?: CVE-2019-2391 is a medium-severity vulnerability in MongoDB Js-Bson, classified under Deserialization of Untrusted Data. CVSS score: 4.2/10. Published 2020-03-31.
How severe is CVE-2019-2391?: Medium severity. CVSS v3 base score is 4.2 out of 10.
Is CVE-2019-2391 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.