What is CVE-2021-23397?

CVE-2021-23397 is a medium-severity vulnerability in Merge Project, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 5.6/10. Published 2022-07-25.

How severe is CVE-2021-23397?

Medium severity. CVSS v3 base score is 5.6 out of 10.

Prototype Pollution in Merge Project

CVE-2021-23397

All versions of package @ianwalter/merge are vulnerable to Prototype Pollution via the main (merge) function. Maintainer suggests using @generates/merger instead.

Vulnerability class: Prototype Pollution

Published 2022-07-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.6 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.008 (56.9th percentile), scored 2026-10-24.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 57th percentile — 56.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: +0.000

Affected products

Merge Project
@Ianwalter/merge — versions 0

Weakness classification (CWE)

CWE-1321 — Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution)

References

security.snyk.io/vuln/SNYK-JS-IANWALTERMERGE-1311022 (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-23397?: CVE-2021-23397 is a medium-severity vulnerability in Merge Project, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 5.6/10. Published 2022-07-25.
How severe is CVE-2021-23397?: Medium severity. CVSS v3 base score is 5.6 out of 10.