CVE-2026-33940— Handlebars.js has JavaScript Injection via AST Type Confusion when passing an object as dynamic partial

Handlebars.js has JavaScript Injection via AST Type Confusion when passing an object as dynamic partial

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('handlebars/runtime')`). 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 (`{{> (lookup ...)}}`) when context data is user-controlled.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

对生成代码的控制不恰当(代码注入)

handlebars 安全漏洞

handlebars是一款语义化的Web模板系统。 Handlebars 4.7.8及之前版本存在安全漏洞，该漏洞源于特制对象可绕过resolvePartial中的所有条件防护，可能导致攻击者执行任意命令，引发服务器端远程代码执行。

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