Arbitrary Code Injection Affecting prism package, versions <5.14.3-r13


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.06% (19th percentile)

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  • Snyk IDSNYK-CHAINGUARDLATEST-PRISM-15878788
  • published3 Apr 2026
  • disclosed27 Mar 2026

Introduced: 27 Mar 2026

NewCVE-2026-33940  (opens in a new tab)
CWE-94  (opens in a new tab)
CWE-843  (opens in a new tab)

How to fix?

Upgrade Chainguard prism to version 5.14.3-r13 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream prism package and not the prism package as distributed by Chainguard. See How to fix? for Chainguard relevant fixed versions and status.

Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, a crafted object placed in the template context can bypass all conditional guards in resolvePartial() and cause invokePartial() to return undefined. The Handlebars runtime then treats the unresolved partial as a source that needs to be compiled, passing the crafted object to env.compile(). Because the object is a valid Handlebars AST containing injected code, the generated JavaScript executes arbitrary commands on the server. The attack requires the adversary to control a value that can be returned by a dynamic partial lookup. Version 4.7.9 fixes the issue. Some workarounds are available. First, use the runtime-only build (require(&#39;handlebars/runtime&#39;)). Without compile(), the fallback compilation path in invokePartial is unreachable. Second, sanitize context data before rendering: Ensure no value in the context is a non-primitive object that could be passed to a dynamic partial. Third, avoid dynamic partial lookups ({{&gt; (lookup ...)}}) when context data is user-controlled.

CVSS Base Scores

version 3.1