CVE-2026-106445

Description

Handlebars provides the power necessary to let users build semantic templates. From 4.0.0 until 4.7.10, Handlebars lookupProperty returns Function.prototype.constructor before applying the prototype-access deny list because constructor is an own property of Function.prototype. When an attacker can render a controlled template with allowProtoMethodsByDefault enabled and an accessible function in the template context, the template can traverse from that function through its prototype to Function.prototype and then obtain the Function constructor through the own-property bypass. This permits attacker-controlled JavaScript to execute with the server application's privileges. This issue is fixed in version 4.7.10.

References

https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-p8wg-vrv2-v86f

https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.10

https://github.com/handlebars-lang/handlebars.js/pull/2185

https://github.com/handlebars-lang/handlebars.js/commit/ceec388abe1d1aac8f6369860d5f390fa71ef4fa

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-93952

Details

Source: Mitre, NVD

Named Vulnerability: GHSA-p8wg-vrv2-v86f

Risk Information

CVSS v2

CVSS v3

CVSS v4

EPSS