Is CVE-2026-106446 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-106446 being exploited in the wild.

How severe is CVE-2026-106446?

Critical severity, with a CVSS score of 9.8, published 6 October 2026.

Which products and versions are affected?

Handlebars.js 4.0.0 through 4.7.9; handlebars (npm) >= 4.0.0, <= 4.7.9, SEMVER:introduced=4.0.0,fixed=4.7.10.

How is CVE-2026-106446 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-106446?

Check whether you run Handlebars.js or handlebars (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-106446: Handlebars AST validation bypass in compile and precompile

Q: Is there a fix for CVE-2026-106446?

Yes. handlebars (npm): upgrade to 4.7.10 or later. Until then: Applications should only pass template strings to compile() and precompile(), never untrusted AST objects. Do not accept pre-parsed AST input from users or external sources. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-106446 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-106446?

Check whether you run Handlebars.js or handlebars (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-106446 · Severity: critical · CVSS 9.8 · Published 2026-10-06

Handlebars is a template engine that compiles templates into JavaScript code. Versions 4.0.0 through 4.7.9 fail to validate untrusted abstract syntax tree (AST) objects passed to compile() and precompile(), allowing attackers to inject arbitrary JavaScript code that executes on the server. If an application accepts user-supplied AST objects instead of template strings, an attacker can achieve remote code execution.

Technologies: Handlebars.js, handlebars (npm). Vendors: Handlebars, npm.

Quick answers

Is CVE-2026-106446 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-106446 being exploited in the wild.
How severe is CVE-2026-106446?: Critical severity, with a CVSS score of 9.8, published 6 October 2026.
Which products and versions are affected?: Handlebars.js 4.0.0 through 4.7.9; handlebars (npm) >= 4.0.0, <= 4.7.9, SEMVER:introduced=4.0.0,fixed=4.7.10.
Is there a fix for CVE-2026-106446?: Yes. handlebars (npm): upgrade to 4.7.10 or later. Until then: Applications should only pass template strings to compile() and precompile(), never untrusted AST objects. Do not accept pre-parsed AST input from users or external sources. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-106446 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-106446?: Check whether you run Handlebars.js or handlebars (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

handlebars (npm): upgrade to 4.7.10 or later
```
npm install handlebars@4.7.10
```

Applications should only pass template strings to compile() and precompile(), never untrusted AST objects. Do not accept pre-parsed AST input from users or external sources.

Technical details

The vulnerability exists in Handlebars compile() and precompile() functions which accept pre-parsed AST objects but perform incomplete validation. An attacker can inject JavaScript expressions via unchecked AST fields including Program.blockParams.length, PathExpression depth parameters, StringLiteral.value non-string values, and PathExpression.original non-string values. The compiler emits these unvalidated values into generated JavaScript, leading to code execution when the compiled template is rendered or when precompiled output is loaded. This bypasses earlier AST validation introduced for CVE-2026-33937.

Affected products

Handlebars Handlebars.js 4.0.0 through 4.7.9

Identifiers

CVE-2026-106446
GHSA-8r5x-fm3f-whwj

Timeline

2026-10-06: disclosed: CVE-2026-106446 published

References

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