CVE catalog
CVE-2026-33938
Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, the `@partial-block` special variable is stored in the template data context and is reac
- Severity
- High · CVSS 8.1
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.72% · Oct 25, 2026
Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, the `@partial-block` special variable is stored in the template data context and is reachable and mutable from within a template via helpers that accept arbitrary objects. When a helper overwrites `@partial-block` with a crafted Handlebars AST, a subsequent invocation of `{{> @partial-block}}` compiles and executes that AST, enabling arbitrary JavaScript execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. First, use the runtime-only build (`require('handlebars/runtime')`). The `compile()` method is absent, eliminating the vulnerable fallback path. Second, audit registered helpers for any that write arbitrary values to context objects. Helpers should treat context data as read-only. Third, avoid registering helpers from third-party packages (such as `handlebars-helpers`) in contexts where templates or context data can be influenced by untrusted input.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | node-handlebars | sid | 3:4.7.10-1 | fixed |
| Debian | node-handlebars | forky | 3:4.7.10-1 | fixed |
| Debian | node-handlebars | trixie | 3:4.7.7+~4.1.0-1 | vulnerable |
| Debian | node-handlebars | bookworm | 3:4.7.7+~4.1.0-1 | vulnerable |
| Cpe | node-handlebars | Not reported | Not reported | vulnerable |
| Cpe | handlebars | Not reported | 4.7.9 | fixed |
| Cpe | handlebars | Not reported | 4.7.9 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | node-handlebars | source | sid | 3:4.7.9-1 | not yet assigned | Not reported | [1132141] |
| Debian | node-handlebars | source | forky | 3:4.7.9-1 | not yet assigned | Not reported | [1132141] |
| Debian | node-handlebars | source | trixie | (unfixed) | not yet assigned | Not reported | [1132141] |
| Debian | node-handlebars | source | bookworm | (unfixed) | not yet assigned | Not reported | [1132141] |
| Cpe | handlebars | cpe | Not reported | 4.7.9 | Not reported | Not reported | Not reported |
| Cpe | handlebars | cpe | Not reported | 4.7.9 | Not reported | NVD-CVE-2026-33938 | Not reported |
Notes
[trixie] node-handlebars: Minor issue [bookworm] node-handlebars: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [handlebars]Affected
Source package: [node-handlebars]
Details (2)
3:4.7.7+~4.1.0-1· all · bookwormAffected
nvd · node-handlebars · debian · bookworm; nvd · node-handlebars · debian · 12
3:4.7.7+~4.1.0-1· all · bookwormAffected
nvd · node-handlebars · debian · bookworm; nvd · node-handlebars · debian · 12
- [libjs-handlebars]Affected
Source package: [node-handlebars]
Details (2)
3:4.7.7+~4.1.0-1· all · bookwormAffected
nvd · node-handlebars · debian · bookworm; nvd · node-handlebars · debian · 12
3:4.7.7+~4.1.0-1· all · bookwormAffected
nvd · node-handlebars · debian · bookworm; nvd · node-handlebars · debian · 12
- [libjs-handlebars.runtime]Affected
Source package: [node-handlebars]
Details (2)
3:4.7.7+~4.1.0-1· all · bookwormAffected
nvd · node-handlebars · debian · bookworm; nvd · node-handlebars · debian · 12
3:4.7.7+~4.1.0-1· all · bookwormAffected
nvd · node-handlebars · debian · bookworm; nvd · node-handlebars · debian · 12
[Debian 13 (Trixie)]
- [handlebars]Affected
Source package: [node-handlebars]
Details (2)
3:4.7.7+~4.1.0-1· all · trixieAffected
nvd · node-handlebars · debian · 13
3:4.7.7+~4.1.0-1· all · trixieAffected
nvd · node-handlebars · debian · 13
- [libjs-handlebars]Affected
Source package: [node-handlebars]
Details (2)
3:4.7.7+~4.1.0-1· all · trixieAffected
nvd · node-handlebars · debian · 13
3:4.7.7+~4.1.0-1· all · trixieAffected
nvd · node-handlebars · debian · 13
- [libjs-handlebars.runtime]Affected
Source package: [node-handlebars]
Details (2)
3:4.7.7+~4.1.0-1· all · trixieAffected
nvd · node-handlebars · debian · 13
3:4.7.7+~4.1.0-1· all · trixieAffected
nvd · node-handlebars · debian · 13
Observed:
References
- [https://access.redhat.com/errata/RHSA-2026:10175]
- [https://access.redhat.com/errata/RHSA-2026:34342]
- [https://access.redhat.com/security/cve/CVE-2026-33938]
- [https://bugzilla.redhat.com/show_bug.cgi?id=2452525]
- [https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2]
- [https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9]
- [https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-3mfm-83xf-c92r]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-33938]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-33938]
- [https://security-tracker.debian.org/tracker/CVE-2026-33938]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33938.json]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-3655.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]