StackPrism

npm package

handlebars 4.0.1 vulnerabilities, and the version that fixes all of them

handlebars 4.0.1 has 20 known vulnerabilities (16 rated high or critical); 4.7.10 fixes all of them.

npm (opens in a new tab) describes it as “Handlebars provides the power necessary to let you build semantic templates effectively with no frustration”

Known vulnerabilities
20
16 rated high or critical
Released
Sep 3, 2015
Latest is 4.7.10
Downloads last week
53
Under 1% of handlebars downloads
Licence
MIT
OpenSSF Scorecard
5.2/10
wycats/handlebars.js (opens in a new tab)
Pulls in
15 packages
Resolved by deps.dev

What to upgrade to

4.7.10 is the closest release with no known vulnerabilities.

  • 4.7.10Upgrade to this

    Fixes all 20 known vulnerabilities and the newest 4.x release and the latest release. Released Oct 5, 2026.

    No known vulnerabilities

4.7.10 came out on Oct 5, 2026. A coding agent trained before then doesn’t know it exists, so it may suggest an older release. AI knowledge cutoff dates

Hand the fix to your coding agent

One task with the upgrade, the file to change and why. Paste it into Claude Code, Cursor or Codex.

Findings

Every advisory for handlebars 4.0.1

Known exploited first (CISA KEV), then by how likely they are to be exploited (FIRST EPSS), then by severity. Each id links to its OSV.dev record.

  1. CriticalCVE-2019-19919 on OSV.dev (opens in a new tab)GHSA-w457-6q6x-cgp9EPSS: top 6%

    Prototype Pollution in handlebars

    Fixed in 4.3.0. Published Dec 26, 2019.

  2. CriticalCVE-2021-23369 on OSV.dev (opens in a new tab)GHSA-f2jv-r9rf-7988EPSS: top 6%

    Remote code execution in handlebars when compiling templates

    Fixed in 4.7.7. Published May 6, 2021.

  3. WarningCVE-2026-33916 on OSV.dev (opens in a new tab)GHSA-2qvq-rjwj-gvw9EPSS: top 6%

    Handlebars.js has Prototype Pollution Leading to XSS through Partial Template Injection

    Fixed in 4.7.9. Published Mar 26, 2026.

  4. CriticalCVE-2021-23383 on OSV.dev (opens in a new tab)GHSA-765h-qjxv-5f44EPSS: top 9%

    Prototype Pollution in handlebars

    Fixed in 4.7.7. Published Feb 10, 2022.

  5. CriticalCVE-2019-20922 on OSV.dev (opens in a new tab)GHSA-62gr-4qp9-h98fEPSS: top 11%

    Regular Expression Denial of Service in Handlebars

    Fixed in 4.4.5. Published Feb 10, 2022.

  6. CriticalCVE-2019-20920 on OSV.dev (opens in a new tab)GHSA-3cqr-58rm-57f8EPSS: top 13%

    Arbitrary Code Execution in Handlebars

    Fixed in 4.5.3. Published Feb 10, 2022.

  7. CriticalCVE-2026-33937 on OSV.dev (opens in a new tab)GHSA-2w6w-674q-4c4qEPSS: top 23%

    Handlebars.js has JavaScript Injection via AST Type Confusion

    Fixed in 4.7.9. Published Mar 27, 2026.

  8. CriticalCVE-2026-33938 on OSV.dev (opens in a new tab)GHSA-3mfm-83xf-c92rEPSS: top 43%

    Handlebars.js has JavaScript Injection via AST Type Confusion by tampering @partial-block

    Fixed in 4.7.9. Published Mar 27, 2026.

  9. CriticalCVE-2026-33940 on OSV.dev (opens in a new tab)GHSA-xhpv-hc6g-r9c6EPSS: top 45%

    Handlebars.js has JavaScript Injection via AST Type Confusion when passing an object as dynamic partial

    Fixed in 4.7.9. Published Mar 27, 2026.

  10. CriticalCVE-2026-33939 on OSV.dev (opens in a new tab)GHSA-9cx6-37pm-9jffEPSS: top 46%

    Handlebars.js has Denial of Service via Malformed Decorator Syntax in Template Compilation

    Fixed in 4.7.9. Published Mar 27, 2026.

  11. CriticalCVE-2026-106446 on OSV.dev (opens in a new tab)GHSA-8r5x-fm3f-whwjEPSS: top 51%

    Handlebars: JavaScript Injection via AST Type Confusion in compile (bypass of CVE-2026-33937)

    Fixed in 4.7.10. Published Oct 8, 2026.

  12. CriticalCVE-2026-106445 on OSV.dev (opens in a new tab)GHSA-p8wg-vrv2-v86fEPSS: top 67%

    Handlebars: JavaScript Injection via Own Property Check Bypass

    Fixed in 4.7.10. Published Oct 8, 2026.

  13. WarningCVE-2026-106444 on OSV.dev (opens in a new tab)GHSA-xw65-4hp5-5hc7EPSS: top 80%

    Handlebars: JavaScript Injection via Unsafe Inline Embedding of Precompiled Templates

    Fixed in 4.7.10. Published Oct 8, 2026.

  14. CriticalCVE-2026-33941 on OSV.dev (opens in a new tab)GHSA-xjpj-3mr7-gcpfEPSS: top 89%

    Handlebars.js has JavaScript Injection in CLI Precompiler via Unescaped Names and Options

    Fixed in 4.7.9. Published Mar 27, 2026.

  15. CriticalGHSA-q2c6-c6pm-g3gh on OSV.dev (opens in a new tab)

    Arbitrary Code Execution in handlebars

    Fixed in 4.5.3. Published Sep 4, 2020.

  16. CriticalGHSA-g9r4-xpmj-mj65 on OSV.dev (opens in a new tab)

    Prototype Pollution in handlebars

    Fixed in 4.5.3. Published Sep 4, 2020.

  17. CriticalGHSA-2cf5-4w76-r9qv on OSV.dev (opens in a new tab)

    Arbitrary Code Execution in handlebars

    Fixed in 4.5.2. Published Sep 4, 2020.

  18. CriticalGHSA-q42p-pg8m-cqh6 on OSV.dev (opens in a new tab)

    Prototype Pollution in handlebars

    Fixed in 4.0.14. Published Jun 5, 2019.

  19. WarningGHSA-f52g-6jhx-586p on OSV.dev (opens in a new tab)

    Denial of Service in handlebars

    Fixed in 4.4.5. Published Sep 3, 2020.

  20. LowGHSA-442j-39wm-28r2 on OSV.dev (opens in a new tab)

    Handlebars.js has a Property Access Validation Bypass in container.lookup

    Fixed in 4.7.9. Published Mar 29, 2026.

Who is still on a vulnerable handlebars

83% of last week’s 43.4M handlebars downloads went to versions with known vulnerabilities.

From npm’s per-version download counts for the last 7 days, each version checked against OSV.dev. The versions checked cover over 99% of downloads.

Is handlebars the only one?

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How this page is checked

StackPrism asks OSV.dev which advisories affect exactly handlebars 4.0.1, merges duplicates filed under several ids, and ranks them with CISA’s Known Exploited Vulnerabilities list and FIRST EPSS. Release dates and deprecation come from deps.dev and npm. No AI writes this page: every sentence comes from that data, refreshed every few hours.

Last checked against npm, OSV.dev, deps.dev, CISA KEV and FIRST EPSS.