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DEBIAN-CVE-2026-53550

Type: advisorySource: OSV1 source record

js-yaml is a JavaScript YAML parser and dumper. Prior to 4.2.0 and 3.15.0, a crafted YAML document can trigger algorithmic CPU exhaustion in js-yaml merge-key processing (<<) by repeating the same alias many times in a merge sequence. This causes quadratic parse-time behavior relative to input size and can block a Node.js worker/event loop for seconds with a relatively small payload (tens of KB), resulting in denial of service. The issue is in merge handling inside lib/loader.js. This vulnerability is fixed in 4.2.0 and 3.15.0.

Announced Source revision 1
Original source ↗

DEBIAN-CVE-2026-53550

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-2026-53550

node-js-yaml

Source reference: /affected/0/package/name

Affected versions
4.1.0+dfsg+~4.0.5-7

Source reference: /affected/0/versions

4.1.1+dfsg+~4.0.9-1

Source reference: /affected/0/versions

4.2.0+~4.0.9-1

Source reference: /affected/0/versions

4.2.0+~4.0.9-2

Source reference: /affected/0/versions

4.3.2+~4.0.9-1

Source reference: /affected/0/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

node-js-yaml

Source reference: /affected/1/package/name

Affected versions
4.1.0+dfsg+~4.0.5-7

Source reference: /affected/1/versions

4.1.1+dfsg+~4.0.9-1

Source reference: /affected/1/versions

4.2.0+~4.0.9-1

Source reference: /affected/1/versions

4.2.0+~4.0.9-2

Source reference: /affected/1/versions

4.3.2+~4.0.9-1

Source reference: /affected/1/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

node-js-yaml

Source reference: /affected/2/package/name

Affected versions
4.1.0+dfsg+~4.0.5-7

Source reference: /affected/2/versions

4.1.1+dfsg+~4.0.9-1

Source reference: /affected/2/versions

Fixed versions
4.2.0+~4.0.9-1

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-js-yaml",
      "purl": "pkg:deb/debian/node-js-yaml?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "4.1.0+dfsg+~4.0.5-7",
      "4.1.1+dfsg+~4.0.9-1",
      "4.2.0+~4.0.9-1",
      "4.2.0+~4.0.9-2",
      "4.3.2+~4.0.9-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-53550.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "node-js-yaml",
      "purl": "pkg:deb/debian/node-js-yaml?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "4.1.0+dfsg+~4.0.5-7",
      "4.1.1+dfsg+~4.0.9-1",
      "4.2.0+~4.0.9-1",
      "4.2.0+~4.0.9-2",
      "4.3.2+~4.0.9-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-53550.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "4.2.0+~4.0.9-1"
          }
        ]
      }
    ],
    "package": {
      "name": "node-js-yaml",
      "purl": "pkg:deb/debian/node-js-yaml?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "4.1.0+dfsg+~4.0.5-7",
      "4.1.1+dfsg+~4.0.9-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-53550.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#57340 · Revision 1
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Publisher date
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