EUVD Vulnerability Catalog

EUVD-2026-93952

Severity: CRITICAL Base Score: 9.2 CVSS Version: 4.0

Vulnerability 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.

CVSS Vector Analysis

Below is the complete, human-readable breakdown of the CVSS metric string: 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

▪ Attack Vector (AV): Network

▪ Attack Complexity (AC): Low

▪ Attack Requirements (AT): Present

▪ Privileges Required (PR): None

▪ User Interaction (UI): None

▪ Vulnerability Confidentiality Impact (VC): High

▪ Vulnerability Integrity Impact (VI): High

▪ Vulnerability Availability Impact (VA): High

▪ Subsequent Confidentiality Impact (SC): None

▪ Subsequent Integrity Impact (SI): None

▪ Subsequent Availability Impact (SA): None

Affected Vendors & Systems

Vendor handlebars-lang

References & Advisory Links

Metadata Profile

Database Authority

European Union Agency for Cybersecurity (ENISA) EUVD

Assigner

GitHub_M

EPSS Probability

0.41

Known Aliases

GHSA-p8wg-vrv2-v86f CVE-2026-106445

Published On

2026-10-06

Last Updated

2026-10-09