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).
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | node-handlebars | 3:4.5.3-1 | — |
| Debian 13 | node-handlebars | 3:4.5.3-1 | — |
| Debian 12 | node-handlebars | 3:4.5.3-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | node-handlebars | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Rhev Manager 4 | ovirt-web-ui | 1.6.5-1.el8ev | RHSA-2020:5179 |
| Red Hat Rhev Manager 4 | rhvm +19 | 4.4.3.8-0.1.el8ev | RHSA-2020:5179 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| npm | handlebars | < 3.0.8 | 3.0.8 | GHSA-3cqr-58rm-57f8 |
| npm | handlebars | >= 4.0.0, < 4.5.3 | 4.5.3 | GHSA-3cqr-58rm-57f8 |
Advisories 1
- RHSA-2020:5179 Red Hat Security Advisory: Red Hat Virtualization security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Oct 13, 2026