CVE-2026-59869 (GCVE-0-2026-59869)

Vulnerability from cvelistv5 – Published: 2026-07-08 15:15 – Updated: 2026-07-09 15:14
VLAI
Title
js-yaml: YAML merge-key chains can force quadratic CPU consumption
Summary
js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 before 3.15.0 and from 4.0.0 before 4.3.0, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in versions 3.15.0 and 4.3.0.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-09 15:14 UTC
CWE
  • CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
Impacted products
Vendor Product Version CPE status
nodeca js-yaml Affected: >= 3.0.0, < 3.15.0
Affected: >= 4.0.0, < 4.3.0
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-59869",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-09T15:14:16.302841Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-09T15:14:29.753Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "js-yaml",
          "vendor": "nodeca",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 3.0.0, \u003c 3.15.0"
            },
            {
              "status": "affected",
              "version": "\u003e= 4.0.0, \u003c 4.3.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 before 3.15.0 and from 4.0.0 before 4.3.0, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in versions 3.15.0 and 4.3.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-407",
              "description": "CWE-407: Inefficient Algorithmic Complexity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-08T15:15:54.675Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m"
        },
        {
          "name": "https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7"
        },
        {
          "name": "https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4"
        },
        {
          "name": "https://github.com/nodeca/js-yaml/releases/tag/3.15.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/nodeca/js-yaml/releases/tag/3.15.0"
        },
        {
          "name": "https://github.com/nodeca/js-yaml/releases/tag/4.3.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/nodeca/js-yaml/releases/tag/4.3.0"
        }
      ],
      "source": {
        "advisory": "GHSA-52cp-r559-cp3m",
        "discovery": "UNKNOWN"
      },
      "title": "js-yaml: YAML merge-key chains can force quadratic CPU consumption"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-59869",
    "datePublished": "2026-07-08T15:15:54.675Z",
    "dateReserved": "2026-07-07T15:41:53.607Z",
    "dateUpdated": "2026-07-09T15:14:29.753Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-59869",
      "date": "2026-08-25",
      "epss": "0.00544",
      "percentile": "0.43263"
    },
    "microsoft_vex": {
      "current_release_date": "2026-07-11T01:07:43.000Z",
      "cve": "CVE-2026-59869",
      "id": "msrc_CVE-2026-59869",
      "initial_release_date": "2026-07-02T00:00:00.000Z",
      "product_status:known_affected": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "js-yaml: YAML merge-key chains can force quadratic CPU consumption",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-59869.json",
      "version": "1"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-59869\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-07-08T16:16:33.423\",\"lastModified\":\"2026-07-13T15:05:34.130\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 before 3.15.0 and from 4.0.0 before 4.3.0, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in versions 3.15.0 and 4.3.0.\"}],\"affected\":[{\"source\":\"security-advisories@github.com\",\"affectedData\":[{\"vendor\":\"nodeca\",\"product\":\"js-yaml\",\"versions\":[{\"version\":\"\u003e= 3.0.0, \u003c 3.15.0\",\"status\":\"affected\"},{\"version\":\"\u003e= 4.0.0, \u003c 4.3.0\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":7.5,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.6}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-07-09T15:14:16.302841Z\",\"id\":\"CVE-2026-59869\",\"options\":[{\"exploitation\":\"poc\"},{\"automatable\":\"yes\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-407\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:nodeca:js-yaml:*:*:*:*:*:node.js:*:*\",\"versionStartIncluding\":\"3.0.0\",\"versionEndExcluding\":\"3.15.0\",\"matchCriteriaId\":\"F0303A0E-076A-425B-9746-6C685213D721\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:nodeca:js-yaml:*:*:*:*:*:node.js:*:*\",\"versionStartIncluding\":\"4.0.0\",\"versionEndExcluding\":\"4.3.0\",\"matchCriteriaId\":\"90F8FD99-9730-49E7-B8AC-97BBF4658327\"}]}]}],\"references\":[{\"url\":\"https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Patch\"]},{\"url\":\"https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Patch\"]},{\"url\":\"https://github.com/nodeca/js-yaml/releases/tag/3.15.0\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Release Notes\"]},{\"url\":\"https://github.com/nodeca/js-yaml/releases/tag/4.3.0\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Release Notes\"]},{\"url\":\"https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Exploit\",\"Vendor Advisory\"]},{\"url\":\"https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m\",\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"tags\":[\"Exploit\",\"Vendor Advisory\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-08-26T04:22:22+00:00",
      "cve": "CVE-2026-59869",
      "id": "CVE-2026-59869",
      "initial_release_date": "2026-07-08T15:15:54.675000+00:00",
      "product_status:fixed": "436",
      "product_status:known_affected": "60",
      "product_status:known_not_affected": "6628",
      "product_status:under_investigation": "73",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "js-yaml: js-yaml: Denial of Service via crafted YAML documents",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-59869.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-59869\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-07-09T15:14:16.302841Z\"}}}], \"references\": [{\"url\": \"https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m\", \"tags\": [\"exploit\"]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2026-07-09T15:14:24.071Z\"}}], \"cna\": {\"title\": \"js-yaml: YAML merge-key chains can force quadratic CPU consumption\", \"source\": {\"advisory\": \"GHSA-52cp-r559-cp3m\", \"discovery\": \"UNKNOWN\"}, \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 7.5, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"HIGH\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"NONE\"}}], \"affected\": [{\"vendor\": \"nodeca\", \"product\": \"js-yaml\", \"versions\": [{\"status\": \"affected\", \"version\": \"\u003e= 3.0.0, \u003c 3.15.0\"}, {\"status\": \"affected\", \"version\": \"\u003e= 4.0.0, \u003c 4.3.0\"}]}], \"references\": [{\"url\": \"https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m\", \"name\": \"https://github.com/nodeca/js-yaml/security/advisories/GHSA-52cp-r559-cp3m\", \"tags\": [\"x_refsource_CONFIRM\"]}, {\"url\": \"https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7\", \"name\": \"https://github.com/nodeca/js-yaml/commit/24f13e79ee1343a7e30bd6f6c9d9cdbf0ac9b2b7\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4\", \"name\": \"https://github.com/nodeca/js-yaml/commit/59423c6f8cdc78742ac00e25a4dd39ef16b702e4\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/nodeca/js-yaml/releases/tag/3.15.0\", \"name\": \"https://github.com/nodeca/js-yaml/releases/tag/3.15.0\", \"tags\": [\"x_refsource_MISC\"]}, {\"url\": \"https://github.com/nodeca/js-yaml/releases/tag/4.3.0\", \"name\": \"https://github.com/nodeca/js-yaml/releases/tag/4.3.0\", \"tags\": [\"x_refsource_MISC\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"js-yaml is a JavaScript YAML parser and dumper. From 3.0.0 before 3.15.0 and from 4.0.0 before 4.3.0, js-yaml can spend quadratic CPU time parsing a document whose size grows only linearly when a chain of mappings uses merge keys where each mapping merges the previous one. This issue is fixed in versions 3.15.0 and 4.3.0.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-407\", \"description\": \"CWE-407: Inefficient Algorithmic Complexity\"}]}], \"providerMetadata\": {\"orgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"shortName\": \"GitHub_M\", \"dateUpdated\": \"2026-07-08T15:15:54.675Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-59869\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-07-09T15:14:29.753Z\", \"dateReserved\": \"2026-07-07T15:41:53.607Z\", \"assignerOrgId\": \"a0819718-46f1-4df5-94e2-005712e83aaa\", \"datePublished\": \"2026-07-08T15:15:54.675Z\", \"assignerShortName\": \"GitHub_M\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



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.