CVE-2026-33940
March 27, 2026, 10:16 p.m.
8.1
High
Description
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.
Product(s) Impacted
| Vendor | Product | Versions |
|---|---|---|
| Handlebars |
|
|
Weaknesses
Common security weaknesses mapped to this vulnerability.
CWE-94
Improper Control of Generation of Code ('Code Injection')
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
*CPE(s)
Affected systems and software identified for this CVE.
| Type | Vendor | Product | Version | Update | Edition | Language | Software Edition | Target Software | Target Hardware | Other Information |
|---|---|---|---|---|---|---|---|---|---|---|
| a | handlebars | handlebars | 4.0.0-4.7.8 | / | / | / | / | / | / | / |
| a | handlebars | handlebars | <4.7.9 | / | / | / | / | / | / | / |
Tags
CVSS Score
CVSS Data - 3.1
- Attack Vector: NETWORK
- Attack Complexity: HIGH
- Privileges Required: NONE
- Scope: UNCHANGED
- Confidentiality Impact: HIGH
- Integrity Impact: HIGH
- Availability Impact: HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Timeline
Published: March 27, 2026, 10:16 p.m.
Last Modified: March 27, 2026, 10:16 p.m.
Last Modified: March 27, 2026, 10:16 p.m.
Status : Received
CVE has been recently published to the CVE List and has been received by the NVD.
More infoSource
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.