Critical
node-handlebars — security advisory
Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. Validate input type before calling `Handlebars.compile()`; ensure the argument is always a `string`, never a plain object or JSON-deserialized value. Use the Handlebars runtime-only build (`handlebars/runtime`) on the server if templates are pre-compiled at build time; `compile()` will be unavailable.
- Products
- node-handlebars
- Affected versions
- 3:4.0.10-5, 3:4.1.0-1, 3:4.5.3-1, 3:4.7.2-1, 3:4.7.6+~4.1.0-2, 3:4.7.7+~4.1.0-1, 3:4.7.9-5
- Fixed versions
- Not specified
- CVEs
- CVE-2026-33937
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:43 UTC · Revision 1
Source evidence
Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. Validate input type before calling `Handlebars.compile()`; ensure the argument is always a `string`, never a plain object or JSON-deserialized value. Use the Handlebars runtime-only build (`handlebars/runtime`) on the server if templates are pre-compiled at build time; `compile()` will be unavailable.
osv:UBUNTU-CVE-2026-33937
node-handlebars
Fixed versions: Not specified
node-handlebars
Fixed versions: Not specified
node-handlebars
Fixed versions: Not specified
node-handlebars
Fixed versions: Not specified
node-handlebars
Fixed versions: Not specified
node-handlebars
Fixed versions: Not specified
node-handlebars
Fixed versions: Not specified
Complete source record
{
"id": "1c1f819ebd731865ae623afd0e5b154352b501ae9f24f26e3f38fb878b96258e",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-33937",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-33937",
"summary": "Handlebars provides the power necessary to let users build semantic templates. In versions 4.0.0 through 4.7.8, `Handlebars.compile()` accepts a pre-parsed AST object in addition to a template string. The `value` field of a `NumberLiteral` AST node is emitted directly into the generated JavaScript without quoting or sanitization. An attacker who can supply a crafted AST to `compile()` can therefore inject and execute arbitrary JavaScript, leading to Remote Code Execution on the server. Version 4.7.9 fixes the issue. Some workarounds are available. Validate input type before calling `Handlebars.compile()`; ensure the argument is always a `string`, never a plain object or JSON-deserialized value. Use the Handlebars runtime-only build (`handlebars/runtime`) on the server if templates are pre-compiled at build time; `compile()` will be unavailable.",
"evidence": "osv:UBUNTU-CVE-2026-33937",
"products": [
{
"name": {
"value": "node-handlebars",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3:4.0.10-5",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "node-handlebars",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3:4.1.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "3:4.5.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "3:4.7.2-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "node-handlebars",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3:4.7.6+~4.1.0-2",
"evidence": "/affected/2/versions"
},
{
"value": "3:4.7.7+~4.1.0-1",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "node-handlebars",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3:4.7.7+~4.1.0-1",
"evidence": "/affected/3/versions"
}
]
},
{
"name": {
"value": "node-handlebars",
"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3:4.7.7+~4.1.0-1",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
"value": "node-handlebars",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3:4.7.7+~4.1.0-1",
"evidence": "/affected/5/versions"
},
{
"value": "3:4.7.9-5",
"evidence": "/affected/5/versions"
}
]
},
{
"name": {
"value": "node-handlebars",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3:4.7.7+~4.1.0-1",
"evidence": "/affected/6/versions"
}
]
}
],
"severity": "critical",
"structured": {
"id": "UBUNTU-CVE-2026-33937",
"aliases": [
"UBUNTU-CVE-2026-33937"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/ubuntu/node-handlebars?arch=source&distro=bionic",
"ecosystem": "Ubuntu:18.04:LTS"
},
"versions": [
"3:4.0.10-5"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33937.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "handlebars",
"binary_version": "3:4.0.10-5"
},
{
"binary_name": "libjs-handlebars",
"binary_version": "3:4.0.10-5"
},
{
"binary_name": "libjs-handlebars.runtime",
"binary_version": "3:4.0.10-5"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/ubuntu/node-handlebars?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"3:4.1.0-1",
"3:4.5.3-1",
"3:4.7.2-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33937.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "handlebars",
"binary_version": "3:4.7.2-1"
},
{
"binary_name": "libjs-handlebars",
"binary_version": "3:4.7.2-1"
},
{
"binary_name": "libjs-handlebars.runtime",
"binary_version": "3:4.7.2-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/ubuntu/node-handlebars?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
"3:4.7.6+~4.1.0-2",
"3:4.7.7+~4.1.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33937.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "handlebars",
"binary_version": "3:4.7.7+~4.1.0-1"
},
{
"binary_name": "libjs-handlebars",
"binary_version": "3:4.7.7+~4.1.0-1"
},
{
"binary_name": "libjs-handlebars.runtime",
"binary_version": "3:4.7.7+~4.1.0-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/ubuntu/node-handlebars?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"3:4.7.7+~4.1.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33937.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "handlebars",
"binary_version": "3:4.7.7+~4.1.0-1"
},
{
"binary_name": "libjs-handlebars",
"binary_version": "3:4.7.7+~4.1.0-1"
},
{
"binary_name": "libjs-handlebars.runtime",
"binary_version": "3:4.7.7+~4.1.0-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/ubuntu/node-handlebars?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
"3:4.7.7+~4.1.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33937.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "handlebars",
"binary_version": "3:4.7.7+~4.1.0-1"
},
{
"binary_name": "libjs-handlebars",
"binary_version": "3:4.7.7+~4.1.0-1"
},
{
"binary_name": "libjs-handlebars.runtime",
"binary_version": "3:4.7.7+~4.1.0-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/ubuntu/node-handlebars?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"3:4.7.7+~4.1.0-1",
"3:4.7.9-5"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33937.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "handlebars",
"binary_version": "3:4.7.9-5"
},
{
"binary_name": "libjs-handlebars",
"binary_version": "3:4.7.9-5"
},
{
"binary_name": "libjs-handlebars.runtime",
"binary_version": "3:4.7.9-5"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "node-handlebars",
"purl": "pkg:deb/ubuntu/node-handlebars?arch=source&distro=resolute",
"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"3:4.7.7+~4.1.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33937.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "handlebars",
"binary_version": "3:4.7.7+~4.1.0-1"
},
{
"binary_name": "libjs-handlebars",
"binary_version": "3:4.7.7+~4.1.0-1"
},
{
"binary_name": "libjs-handlebars.runtime",
"binary_version": "3:4.7.7+~4.1.0-1"
}
]
}
}
],
"modified": "2026-10-17T12:58:51.634769266Z",
"provider": "osv",
"upstream": [
"CVE-2026-33937"
],
"references": [
"https://ubuntu.com/security/CVE-2026-33937",
"https://www.cve.org/CVERecord?id=CVE-2026-33937",
"https://github.com/handlebars-lang/handlebars.js/security/advisories/GHSA-2w6w-674q-4c4q",
"https://github.com/handlebars-lang/handlebars.js/commit/68d8df5a88e0a26fe9e6084c5c6aaebe67b07da2",
"https://github.com/handlebars-lang/handlebars.js/releases/tag/v4.7.9"
]
},
"related_cves": [
{
"value": "CVE-2026-33937",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 359119,
"published_at": "2026-03-27T21:17:00+00:00"
}