Code Injection in handlebars.js - CVE-2026-33940

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Main Vulnerability Database Vulnerabilities #VU124840

Code Injection in handlebars.js - CVE-2026-33940

Published: April 2, 2026


Vulnerability identifier: #VU124840
CSH Severity: High
CVSS v4: 9.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-33940
CWE-ID: CWE-94
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to execute arbitrary code.

The vulnerability exists due to improper control of code generation caused by type confusion in dynamic partial handling in lib/handlebars/runtime.js when processing a dynamic partial lookup that returns a crafted object from the template context. A remote attacker can supply a crafted object as the looked-up dynamic partial value to execute arbitrary code.

The issue affects server-side rendering scenarios in which user-controlled context data can be returned by a dynamic partial lookup, such as {{> (lookup . "key")}}. Exploitation requires control over a value returned by the dynamic partial lookup.


Affected software

handlebars.js
Storage Defender Copy Data Management
Fedora
IBM App Connect Enterprise
nextcloud

How to mitigate CVE-2026-33940

Install security update from vendor's website.

handlebars.js - update to 4.7.9
Storage Defender Copy Data Management - update to 2.3.1.0
IBM App Connect Enterprise - addressed in versions 12.0.12.25, 13.0.7.1
nextcloud - addressed in versions 33.0.3-1.el10_2, 33.0.3-1.el10_3, 33.0.3-1.fc42, 33.0.3-1.fc43, 33.0.3-1.fc44

External References

Related Security Bulletins