CriticalGHSA-w457-6q6x-cgp9CVE-2019-19919
Prototype Pollution in handlebars
Published 26 Dec 2019 · Updated 10 Sept 2026
Affected packages
handlebarsnpm
- Affected
- >=4.0.0 <4.3.0
- Fixed in
- 4.3.0
Update to the fixed version for your release line, for example:
npm install handlebars@4.3.0handlebarsnpm
- Affected
- <3.0.8
- Fixed in
- 3.0.8
Update to the fixed version for your release line, for example:
npm install handlebars@3.0.8Details
Versions of handlebars prior to 3.0.8 or 4.3.0 are vulnerable to Prototype Pollution leading to Remote Code Execution. Templates may alter an Objects' __proto__ and __defineGetter__ properties, which may allow an attacker to execute arbitrary code through crafted payloads.
Recommendation
Upgrade to version 3.0.8, 4.3.0 or later.
Is GHSA-w457-6q6x-cgp9 in any of your client repos?
Checking one package by hand is fine. Checking it across forty client projects is not. NPMscan reads the lockfiles in every GitHub repo you pick, finds each project with an affected handlebars, and gives you the command that fixes it.
References
- Advisorynvd.nist.gov/vuln/detail/CVE-2019-19919
- Linkgithub.com/wycats/handlebars.js/issues/1558
- Linkgithub.com/handlebars-lang/handlebars.js/commit/156061eb7707575293613d7fdf90e2bdaac029ee
- Linkgithub.com/handlebars-lang/handlebars.js/commit/90ad8d97ad2933852fb83fcc054699dc99e094db
- Linkgithub.com/wycats/handlebars.js/commit/2078c727c627f25d4a149962f05c1e069beb18bc
- Linkcve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-19919
- Linkgithub.com/Nerian/bootstrap-wysihtml5-rails/blob/master/vendor/assets/javascripts/bootstrap-wysihtml5/handlebars.runtime.min.js
- Linkgithub.com/Nerian/bootstrap-wysihtml5-rails/tree/master/vendor/assets/javascripts/bootstrap-wysihtml5
- Linkgithub.com/rubysec/ruby-advisory-db/blob/master/gems/bootstrap-wysihtml5-rails/CVE-2019-19919.yml
- Packagegithub.com/wycats/handlebars.js
- Linkwww.tenable.com/security/tns-2021-14
Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.