GHSA-2CF5-4W76-R9QV

Versions of handlebars prior to 3.0.8 or 4.5.2 are vulnerable to Arbitrary Code Execution. The package's lookup helper fails to properly validate templates, allowing attackers to submit templates that execute arbitrary JavaScript in the system. It can be used to run arbitrary code in a server processing Handlebars templates or on a victim's browser (effectively serving as Cross-Site Scripting).

The following template can be used to demonstrate the vulnerability:

	{{#with split as |a|}}
		{{pop (push "alert('Vulnerable Handlebars JS');")}}
		{{#with (concat (lookup join (slice 0 1)))}}
			{{#each (slice 2 3)}}
				{{#with (apply 0 a)}}
					{{.}}
				{{/with}}
			{{/each}}
		{{/with}}
	{{/with}}
{{/with}}```


## Recommendation

Upgrade to version 3.0.8, 4.5.2 or later.

Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.

GHSA-2CF5-4W76-R9QV has a CVSS score of 7.3 (High). The vector is requires local access, low privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.0.8, 4.5.2); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is GHSA-2CF5-4W76-R9QV? GHSA-2CF5-4W76-R9QV is a high-severity code injection vulnerability in handlebars (npm), affecting versions < 3.0.8. It is fixed in 3.0.8, 4.5.2. Untrusted input is evaluated as executable code within the application's runtime environment.
2. How severe is GHSA-2CF5-4W76-R9QV? GHSA-2CF5-4W76-R9QV has a CVSS score of 7.3 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of handlebars are affected by GHSA-2CF5-4W76-R9QV? handlebars (npm) versions < 3.0.8 is affected.
4. Is there a fix for GHSA-2CF5-4W76-R9QV? Yes. GHSA-2CF5-4W76-R9QV is fixed in 3.0.8, 4.5.2. Upgrade to this version or later.
5. Is GHSA-2CF5-4W76-R9QV exploitable, and should I be worried? Whether GHSA-2CF5-4W76-R9QV is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether GHSA-2CF5-4W76-R9QV is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix GHSA-2CF5-4W76-R9QV?
   • Upgrade handlebars to 3.0.8 or later
   • Upgrade handlebars to 4.5.2 or later

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