Vulnerability-Lookup

GHSA-WJV4-X9W8-WM3H

Vulnerability from github – Published: 2026-06-19 16:36 – Updated: 2026-06-19 16:36

Summary

Nokogiri: Possible Use-After-Free when setting `Document#root=` to an invalid node type

Details

Summary

Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root. The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault.

Nokogiri 1.19.4 restricts Document#root= to element nodes, raising TypeError for any other node type.

This memory-safety issue affects only the CRuby implementation (libxml2). The JRuby implementation was not affected; the same input validation was added there for behavioral parity.

Severity

The Nokogiri maintainers have evaluated this as low severity. This is only triggered by a programming error. It requires application code to assign a non-element node such as a DTD as the document root via Document#root=. Nokogiri 1.19.4 now raises TypeError instead of allowing a use-after-free. It cannot be triggered by untrusted input or through normal use of the public API.

Mitigation

Upgrade to Nokogiri 1.19.4 or later.

As a workaround, applications that cannot upgrade should avoid assigning a DTD (or any non-element node) via Document#root=.

Credit

This issue was responsibly reported by Zheng Yu from depthfirst.com.

Severity

1.7 (Low)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U

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{
  "affected": [
    {
      "package": {
        "ecosystem": "RubyGems",
        "name": "nokogiri"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.19.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T16:36:59Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Summary\n\n`Nokogiri::XML::Document#root=` validated only that the new root was a `Nokogiri::XML::Node`, allowing a DTD node to be set as the document root. The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault.\n\nNokogiri 1.19.4 restricts `Document#root=` to element nodes, raising `TypeError` for any other node type.\n\nThis memory-safety issue affects only the CRuby implementation (libxml2). The JRuby implementation was not affected; the same input validation was added there for behavioral parity.\n\n### Severity\n\nThe Nokogiri maintainers have evaluated this as low severity. This is only triggered by a programming error. It requires application code to assign a non-element node such as a DTD as the document root via `Document#root=`. Nokogiri 1.19.4 now raises `TypeError` instead of allowing a use-after-free. It cannot be triggered by untrusted input or through normal use of the public API.\n\n### Mitigation\n\nUpgrade to Nokogiri 1.19.4 or later.\n\nAs a workaround, applications that cannot upgrade should avoid assigning a DTD (or any non-element node) via `Document#root=`.\n\n### Credit\n\nThis issue was responsibly reported by Zheng Yu from depthfirst.com.",
  "id": "GHSA-wjv4-x9w8-wm3h",
  "modified": "2026-06-19T16:36:59Z",
  "published": "2026-06-19T16:36:59Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-wjv4-x9w8-wm3h"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/sparklemotion/nokogiri"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Nokogiri: Possible Use-After-Free when setting `Document#root=` to an invalid node type"
}

CVE-2026-57436 (GCVE-0-2026-57436)

Vulnerability from cvelistv5 – Published: 2026-06-25 14:33 – Updated: 2026-06-25 23:27

Title

Nokogiri: Possible Use-After-Free when setting `Document#root=` to an invalid node type

Summary

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root. The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault. This vulnerability is fixed in 1.19.4.

Severity

1.7 (Low)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-416 - Use After Free

Assigner

GitHub_M

References

1 reference

URL	Tags
https://github.com/sparklemotion/nokogiri/securit…	x_refsource_CONFIRM

Impacted products

1 product

Vendor	Product	Version
sparklemotion	nokogiri	Affected: < 1.19.4

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-57436",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-25T23:26:42.649086Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-25T23:27:34.410Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "nokogiri",
          "vendor": "sparklemotion",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.19.4"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root. The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault. This vulnerability is fixed in 1.19.4."
        }
      ],
      "metrics": [
        {
          "cvssV4_0": {
            "attackComplexity": "LOW",
            "attackRequirements": "PRESENT",
            "attackVector": "NETWORK",
            "baseScore": 1.7,
            "baseSeverity": "LOW",
            "privilegesRequired": "NONE",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U",
            "version": "4.0",
            "vulnAvailabilityImpact": "LOW",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-416",
              "description": "CWE-416: Use After Free",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-25T14:33:29.496Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-wjv4-x9w8-wm3h",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-wjv4-x9w8-wm3h"
        }
      ],
      "source": {
        "advisory": "GHSA-wjv4-x9w8-wm3h",
        "discovery": "UNKNOWN"
      },
      "title": "Nokogiri: Possible Use-After-Free when setting `Document#root=` to an invalid node type"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-57436",
    "datePublished": "2026-06-25T14:33:29.496Z",
    "dateReserved": "2026-06-24T13:21:20.729Z",
    "dateUpdated": "2026-06-25T23:27:34.410Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

Action not permitted

GHSA-WJV4-X9W8-WM3H

Summary

Severity

Mitigation

Credit

CVE-2026-57436 (GCVE-0-2026-57436)

Tags

Sightings

Nomenclature