What is CVE-2021-23470?

CVE-2021-23470 is a high-severity vulnerability in Putil-Merge Project, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 8.2/10. Published 2022-02-04.

How severe is CVE-2021-23470?

High severity. CVSS v3 base score is 8.2 out of 10.

Prototype Pollution in Putil-Merge Project

CVE-2021-23470

This affects the package putil-merge before 3.8.0. The merge() function does not check the values passed into the argument. An attacker can supply a malicious value by adjusting the value to include the constructor property. Note: This vulnerability derives from an incomplete fix in https://security.snyk.io/vuln/SNYK-JS-PUTILMERGE-1317077

Vulnerability class: Prototype Pollution

Published 2022-02-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H.

EPSS exploit prediction

EPSS: 0.013 (69.5th percentile), scored 2026-10-24.

Low probability of exploitation in the next 30 days, but still tracked. 70th percentile — 69.5% 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: 0.013 · change: 0.000

Affected products

Putil-Merge Project
Putil-Merge — versions unspecified

Weakness classification (CWE)

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

References

snyk.io/vuln/SNYK-JS-PUTILMERGE-2391487 (Exploit, Vendor Advisory)
github.com/panates/putil-merge/commit/476d00078dfb2827d7c9ee0f2392c81b864f7bc5 (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-23470?: CVE-2021-23470 is a high-severity vulnerability in Putil-Merge Project, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 8.2/10. Published 2022-02-04.
How severe is CVE-2021-23470?: High severity. CVSS v3 base score is 8.2 out of 10.