CVE-2026-33940
Handlebars.js has JavaScript Injection via AST Type Confusion when passing an object as dynamic partial
描述
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.
如何修補 CVE-2026-33940
要修補 CVE-2026-33940,請將受影響套件升級到下列已修補版本。
- —未列出修補版本
- —升級至 4.7.9 或更新版本
CVE-2026-33940 正在被利用嗎?
低 — EPSS 為 0.7%,目前沒有觀察到大規模利用活動。
受影響套件(2)
- from 0
- >= 4.0.0, < 4.7.9