ubuntu-cve-2026-53550
Vulnerability from osv_ubuntu
Published
2026-06-22 16:16
Modified
2026-07-01 21:27
Summary
Details

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.

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-js-yaml",
            "binary_version": "3.10.0+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "node-js-yaml",
        "purl": "pkg:deb/ubuntu/node-js-yaml@3.10.0+dfsg-1?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.9.1+dfsg-1",
        "3.10.0+dfsg-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-js-yaml",
            "binary_version": "3.13.1+dfsg-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "node-js-yaml",
        "purl": "pkg:deb/ubuntu/node-js-yaml@3.13.1+dfsg-2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.13.1+dfsg-2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-js-yaml",
            "binary_version": "4.1.0+dfsg+~4.0.5-6"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "node-js-yaml",
        "purl": "pkg:deb/ubuntu/node-js-yaml@4.1.0+dfsg+~4.0.5-6?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "3.14.1+dfsg+~3.12.6-2",
        "4.1.0+dfsg+~4.0.5-4ubuntu1",
        "4.1.0+dfsg+~4.0.5-5",
        "4.1.0+dfsg+~4.0.5-6"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-js-yaml",
            "binary_version": "4.1.0+dfsg+~4.0.5-7"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "node-js-yaml",
        "purl": "pkg:deb/ubuntu/node-js-yaml@4.1.0+dfsg+~4.0.5-7?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.1.0+dfsg+~4.0.5-7"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-js-yaml",
            "binary_version": "4.1.0+dfsg+~4.0.5-7"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "node-js-yaml",
        "purl": "pkg:deb/ubuntu/node-js-yaml@4.1.0+dfsg+~4.0.5-7?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.1.0+dfsg+~4.0.5-7"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-js-yaml",
            "binary_version": "4.1.1+dfsg+~4.0.9-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "node-js-yaml",
        "purl": "pkg:deb/ubuntu/node-js-yaml@4.1.1+dfsg+~4.0.9-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.1.0+dfsg+~4.0.5-7",
        "4.1.1+dfsg+~4.0.9-1"
      ]
    }
  ],
  "aliases": [],
  "details": "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 (\u003c\u003c) 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.",
  "id": "UBUNTU-CVE-2026-53550",
  "modified": "2026-07-01T21:27:55Z",
  "published": "2026-06-22T16:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-53550"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-53550"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-53550"
  ]
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.