Summary
Handlebars: JavaScript Injection via AST Type Confusion in compile (bypass of CVE-2026-33937)
Impact
An application is affected if untrusted input can reach Handlebars.compile() or Handlebars.precompile() as an object instead of a string. A common way this happens is passing a field from a JSON request body straight to compile().
compile(): arbitrary JavaScript runs in the Node.js process with the application's privileges (remote code execution).precompile(): the injected code is written into the precompiled template and runs wherever that template is loaded, for example in users' browsers.
Untrusted input is evaluated as executable code within the application's runtime environment. Typical impact: arbitrary code execution within the application's privilege context.
CVE-2026-106446 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. 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 (4.7.10); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2026-106446? CVE-2026-106446 is a critical-severity code injection vulnerability in handlebars (npm), affecting versions >= 4.0.0, <= 4.7.9. It is fixed in 4.7.10. Untrusted input is evaluated as executable code within the application's runtime environment.
- How severe is CVE-2026-106446? CVE-2026-106446 has a CVSS score of 9.8 (Critical). 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.
- Which versions of handlebars are affected by CVE-2026-106446? handlebars (npm) versions >= 4.0.0, <= 4.7.9 is affected.
- Is there a fix for CVE-2026-106446? Yes. CVE-2026-106446 is fixed in 4.7.10. Upgrade to this version or later.
- Is CVE-2026-106446 exploitable, and should I be worried? Whether CVE-2026-106446 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
- What actually determines whether CVE-2026-106446 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.
- How do I fix CVE-2026-106446? Upgrade
handlebarsto 4.7.10 or later.