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Arbitrary Code Execution in Handlebars

High severity GitHub Reviewed Published Feb 10, 2022 to the GitHub Advisory Database • Updated Nov 29, 2023

Package

npm handlebars (npm)

Affected versions

< 3.0.8
>= 4.0.0, < 4.5.3

Patched versions

3.0.8
4.5.3

Description

Handlebars before 3.0.8 and 4.x before 4.5.3 is vulnerable to Arbitrary Code Execution. The lookup helper fails to properly validate templates, allowing attackers to submit templates that execute arbitrary JavaScript. This can be used to run arbitrary code on a server processing Handlebars templates or in a victim's browser (effectively serving as XSS).

References

Published by the National Vulnerability Database Sep 30, 2020
Reviewed Apr 22, 2021
Published to the GitHub Advisory Database Feb 10, 2022
Last updated Nov 29, 2023

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
Low

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:L

EPSS score

0.699%
(81st percentile)

Weaknesses

CVE ID

CVE-2019-20920

GHSA ID

GHSA-3cqr-58rm-57f8

Source code

No known source code
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