Reference page — cumulative record through Monday, October 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.

CVE-2021-23383

CVE-2021-23383CRITICAL

n/a handlebars — Prototype Pollution

  AV  AC  PR  UI  S  C  I  A   CVSS    EPSS   %ile   KEV
   N   L   N   N  U  H  H  H    9.8   .0451   91.4     —

AFFECTED
  Product     Versions       Fixed
  handlebars  unspecified –  —

TIMELINE
  Jan 8   Reserved by snyk
  May 4   Published (CNA: snyk)
  Oct 8   EXPLOIT PUBLISHED — CVE-2021-23383 (handlebars). Public exploit reference added.
  Oct 8   RESCORED — CVE-2021-23383 (handlebars). CVSS 5.6 → 9.8 (NVD).

CWE-1321 · CNA: snyk · CVSS v3.1 · 6 references · NVD status: Modified

Description

The package handlebars before 4.7.7 are vulnerable to Prototype Pollution when selecting certain compiling options to compile templates coming from an untrusted source.

Lifecycle

Complete event history — 4 events, chronological
Date	Event	Detail
January 8, 2021	Reserved	Reserved by snyk
May 4, 2021	Published	Published (CNA: snyk)
October 8, 2026	EXPLOIT PUBLISHED	EXPLOIT PUBLISHED — CVE-2021-23383 (handlebars). Public exploit reference added.
October 8, 2026	RESCORED	RESCORED — CVE-2021-23383 (handlebars). CVSS 5.6 → 9.8 (NVD).

Affected

Affected products and packages — 1 row
Vendor	Product / Package	Ecosystem	Version introduced	Fixed
n/a	handlebars	—	unspecified	—

Weaknesses

CWE-1321

References (6)

https://github.com/handlebars-lang/handlebars.js/commit/f0589701698268578199be25285b2ebea1c1e427 [Patch, Third Party Advisory]
https://security.netapp.com/advisory/ntap-20210618-0007/ [Third Party Advisory]
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARS-1279031 [Exploit, Patch, Third Party Advisory]
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWER-1279032 [Exploit, Patch, Third Party Advisory]
https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-1279030 [Exploit, Patch, Third Party Advisory]
https://snyk.io/vuln/SNYK-JS-HANDLEBARS-1279029 [Exploit, Patch, Third Party Advisory]

Authoritative record: CVE-2021-23383 at cve.org

Weaknesses: CWE-1321

About this page

This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-23383 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Monday, October 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.