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DEBIAN-CVE-2026-33938

Type: advisorySource: OSV1 source record

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.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-33938

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-2026-33938

node-handlebars

Source reference: /affected/0/package/name

Affected versions
3:4.7.7+~4.1.0-1

Source reference: /affected/0/versions

3:4.7.9-1

Source reference: /affected/0/versions

3:4.7.9-2

Source reference: /affected/0/versions

3:4.7.9-3

Source reference: /affected/0/versions

3:4.7.9-4

Source reference: /affected/0/versions

3:4.7.9-5

Source reference: /affected/0/versions

3:4.7.9-6

Source 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/versions

3:4.7.9-1

Source reference: /affected/1/versions

3:4.7.9-2

Source reference: /affected/1/versions

3:4.7.9-3

Source reference: /affected/1/versions

3:4.7.9-4

Source reference: /affected/1/versions

3:4.7.9-5

Source reference: /affected/1/versions

3:4.7.9-6

Source 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-2026-33938.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-2026-33938.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-2026-33938.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#55949 · Revision 1
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Publisher date
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