Answer in brief
CVE-2019-19919 records a Critical severity (CVSS 9.8) vulnerability in Prototype Pollution in handlebars. The current sources do not mark it as known exploited. The current feed maps handlebars (npm), handlebars (npm), bootstrap-wysihtml5-rails (rubygems). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps handlebars (npm), handlebars (npm), bootstrap-wysihtml5-rails (rubygems). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| handlebarsnpm | >=4.0.0 <4.3.0 | 4.3.0 |
| handlebarsnpm | >=0 <3.0.8 | 3.0.8 |
| bootstrap-wysihtml5-railsrubygems | >=0.3.3.5 | Not reported |
Published upstream
Dec 26, 2019
Evidence: source:osv:source_dates:source-dates:recordSource modified
Sep 10, 2026
Evidence: source:osv:source_dates:source-dates:recordFirst seen by HOL
Aug 7, 2026
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.
Quoted source text, attributed separately from HOL analysis.