DEBIAN-CVE-2026-33939
Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, when a Handlebars template contains decorator syntax referencing an unregistered decorator (e.g. `{{*n}}`), the compiled template calls `lookupProperty(decorators, "n")`, which returns `undefined`. The runtime then immediately invokes the result as a function, causing an unhandled `TypeError: ... is not a function` that crashes the Node.js process. Any application that compiles user-supplied templates without wrapping the call in a `try/catch` is vulnerable to a single-request Denial of Service. Version 4.7.9 fixes the issue. Some workarounds are available. Wrap compilation and rendering in `try/catch`. Validate template input before passing it to `compile()`; reject templates containing decorator syntax (`{{*...}}`) if decorators are not used in your application. Use the pre-compilation workflow; compile templates at build time and serve only pre-compiled templates; do not call `compile()` at request time.
DEBIAN-CVE-2026-33939
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:DEBIAN-CVE-2026-33939
node-handlebars
Source reference: /affected/0/package/name
- Affected versions
- 3:4.7.7+~4.1.0-1
Source reference:
/affected/0/versions3:4.7.9-1Source reference:
/affected/0/versions3:4.7.9-2Source reference:
/affected/0/versions3:4.7.9-3Source reference:
/affected/0/versions3:4.7.9-4Source reference:
/affected/0/versions3:4.7.9-5Source reference:
/affected/0/versions3:4.7.9-6Source reference:
/affected/0/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
node-handlebars
Source reference: /affected/1/package/name
- Affected versions
- 3:4.7.7+~4.1.0-1
Source reference:
/affected/1/versions3:4.7.9-1Source reference:
/affected/1/versions3:4.7.9-2Source reference:
/affected/1/versions3:4.7.9-3Source reference:
/affected/1/versions3:4.7.9-4Source reference:
/affected/1/versions3:4.7.9-5Source reference:
/affected/1/versions3:4.7.9-6Source reference:
/affected/1/versions - Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
node-handlebars
Source reference: /affected/2/package/name
- Affected versions
- 3:4.7.7+~4.1.0-1
Source reference:
/affected/2/versions - Fixed versions
- 3:4.7.9-1
Source reference:
/affected/2/ranges - Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/debian/node-handlebars?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"3:4.7.7+~4.1.0-1",
"3:4.7.9-1",
"3:4.7.9-2",
"3:4.7.9-3",
"3:4.7.9-4",
"3:4.7.9-5",
"3:4.7.9-6"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33939.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/debian/node-handlebars?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"3:4.7.7+~4.1.0-1",
"3:4.7.9-1",
"3:4.7.9-2",
"3:4.7.9-3",
"3:4.7.9-4",
"3:4.7.9-5",
"3:4.7.9-6"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33939.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3:4.7.9-1"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/debian/node-handlebars?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"3:4.7.7+~4.1.0-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33939.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
]Publisher severity
No explicit severity was provided.
- Event
- #56816 · Revision 1
- Added to Heist Feed
- Publisher date