# CVE-2021-23337 — Lodash

> As of 2026-10-08, CVE-2021-23337 is a HIGH-severity vulnerability in Lodash, CVSS v3.1 7.2, EPSS 21.3% (97.5th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2021-23337, most recently “CVE-2026-4800: Lodash `_.template` Arbitrary Code Injection — Broken 4.18.0 Patch Exposes Supply-Chain Patch-Pinning Risk”.

**Last updated:** 2026-10-08

## What is CVE-2021-23337?

Lodash versions prior to 4.17.21 are vulnerable to Command Injection via the template function.

The record classifies CVE-2021-23337 under weakness class [CWE-94](https://intel.threadlinqs.com/cwe/CWE-94). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs high-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 2096 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.2 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:P/RL:U/RC:C`)
- **EPSS (FIRST):** 21.3% probability of exploitation in the next 30 days, higher than 97.5% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 10/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2021-02-15

## Is CVE-2021-23337 being exploited?

Weaponised exploit code for CVE-2021-23337 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier. A ProjectDiscovery Nuclei detection template exists (`http/cves/2021/CVE-2021-23337.yaml`). It currently carries a trending score of 39 in the Threadlinqs vulnerability feed.

- [khayashi4337/lodash.template-fixed](https://github.com/khayashi4337/lodash.template-fixed) (github)
- [trickest/cve](https://github.com/trickest/cve/blob/main/2021/CVE-2021-23337.md) (trickest)

## Affected products and versions

- **(vendor unspecified)**: Lodash

Affected software packages:

- `npm:lodash` — patched in 4.17.21
- `npm:lodash-es` — patched in 4.17.21
- `npm:lodash.template`
- `npm:lodash-template`
- `rubygems:lodash-rails` — patched in 4.17.21

## How to fix CVE-2021-23337

The record marks a vendor fix as available for CVE-2021-23337. Fixed versions are recorded for 3 packages: npm:lodash 4.17.21, npm:lodash-es 4.17.21, rubygems:lodash-rails 4.17.21. Patch reference: [https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf](https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf). Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

## Threat activity tracking CVE-2021-23337

1 tracked threat in the Threadlinqs corpus references CVE-2021-23337, either in the campaign’s CVE list or as an indicator on the campaign record.

- [CVE-2026-4800: Lodash `_.template` Arbitrary Code Injection — Broken 4.18.0 Patch Exposes Supply-Chain Patch-Pinning Risk](https://intel.threadlinqs.com/threat/TL-2026-2151) — HIGH · 2026-08-26

## Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories, ProjectDiscovery Nuclei. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [security.netapp.com](https://security.netapp.com/advisory/ntap-20210312-0006/)
- [cert-portal.siemens.com](https://cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf)

**Other references**

- [snyk.io](https://snyk.io/vuln/SNYK-JS-LODASH-1040724)
- [snyk.io (SNYK JAVA ORGWEBJARSBOWER 1074928)](https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWER-1074928)
- [snyk.io (SNYK JAVA ORGWEBJARSNPM 1074929)](https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1074929)
- [snyk.io (SNYK JAVA ORGWEBJARS 1074930)](https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARS-1074930)
- [snyk.io (SNYK JAVA ORGWEBJARSBOWERGITHUBLODASH 10)](https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWERGITHUBLODASH-1074931)

_Showing 7 of 13 recorded references._

Canonical: https://intel.threadlinqs.com/cve/CVE-2021-23337
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