Vulnerability-Lookup

GHSA-8678-W3JW-XFC2

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

Summary

Nokogiri: XML::Schema on JRuby allows network requests when NONET is set, bypassing CVE-2020-26247

Details

Summary

The NONET parse option, which Nokogiri turns on by default for Nokogiri::XML::Schema (see CVE-2020-26247), was not correctly enforced on the JRuby implementation. As a result, a schema parsed with default options could still cause external resources to be fetched over the network, potentially enabling SSRF or XXE attacks.

Nokogiri 1.19.4 replaces the scheme denylist with an allowlist. When NONET is enabled, only local resources (a file: scheme, or a relative or absolute path with no scheme) are resolved, and every network scheme is blocked, case-insensitively. This brings the JRuby behavior in line with CRuby.

Only the JRuby implementation is affected. CRuby is not affected, because libxml2's xmlNoNetExternalEntityLoader blocks all network schemes at the I/O layer regardless of scheme or case.

Severity

The Nokogiri maintainers have evaluated this as low severity (CVSS 2.6, CVSS:3.0/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N). It is a bypass of CVE-2020-26247, which was scored the same way.

Mitigation

Upgrade to Nokogiri 1.19.4 or later.

There are no known workarounds for affected versions.

This change properly enforces NONET on JRuby, which is a breaking change for any code that (perhaps unknowingly) relied on the previous behavior to load network resources with default parse options. If you trust your input and want to allow external resources to be accessed over the network, you can explicitly disable NONET, exactly as documented for CVE-2020-26247:

Ensure the input is trusted. Do not enable this option for untrusted input.
Pass a Nokogiri::XML::ParseOptions with the NONET flag turned off:

# allows resources to be accessed over the network for trusted input
schema = Nokogiri::XML::Schema.new(trusted_schema, Nokogiri::XML::ParseOptions.new.nononet)

References

Bypass of: https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-vr8q-g5c7-m54m

Credit

This issue was responsibly reported by @bilerden.

Severity

2.6 (Low)


                  
                    CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N

Show details on source website

JSON

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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-178",
      "CWE-184",
      "CWE-611"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-19T16:36:11Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Summary\n\nThe `NONET` parse option, which Nokogiri turns on by default for `Nokogiri::XML::Schema` (see [CVE-2020-26247](https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-vr8q-g5c7-m54m)), was not correctly enforced on the JRuby implementation. As a result, a schema parsed with default options could still cause external resources to be fetched over the network, potentially enabling SSRF or XXE attacks.\n\nNokogiri 1.19.4 replaces the scheme denylist with an allowlist. When `NONET` is enabled, only local resources (a `file:` scheme, or a relative or absolute path with no scheme) are resolved, and every network scheme is blocked, case-insensitively. This brings the JRuby behavior in line with CRuby.\n\nOnly the JRuby implementation is affected. CRuby is not affected, because libxml2\u0027s `xmlNoNetExternalEntityLoader` blocks all network schemes at the I/O layer regardless of scheme or case.\n\n### Severity\n\nThe Nokogiri maintainers have evaluated this as low severity (CVSS 2.6, `CVSS:3.0/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N`). It is a bypass of CVE-2020-26247, which was scored the same way.\n\n### Mitigation\n\nUpgrade to Nokogiri 1.19.4 or later.\n\nThere are no known workarounds for affected versions.\n\nThis change properly enforces `NONET` on JRuby, which is a breaking change for any code that (perhaps unknowingly) relied on the previous behavior to load network resources with default parse options. If you trust your input and want to allow external resources to be accessed over the network, you can explicitly disable `NONET`, exactly as documented for CVE-2020-26247:\n\n1. Ensure the input is trusted. Do not enable this option for untrusted input.\n2. Pass a `Nokogiri::XML::ParseOptions` with the `NONET` flag turned off:\n\n``` ruby\n# allows resources to be accessed over the network for trusted input\nschema = Nokogiri::XML::Schema.new(trusted_schema, Nokogiri::XML::ParseOptions.new.nononet)\n```\n\n### References\n\n- Bypass of: https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-vr8q-g5c7-m54m\n\n### Credit\n\nThis issue was responsibly reported by @bilerden.",
  "id": "GHSA-8678-w3jw-xfc2",
  "modified": "2026-06-19T16:36:11Z",
  "published": "2026-06-19T16:36:11Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-8678-w3jw-xfc2"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/sparklemotion/nokogiri"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Nokogiri: XML::Schema on JRuby allows network requests when NONET is set, bypassing CVE-2020-26247"
}

CVE-2026-57234 (GCVE-0-2026-57234)

Vulnerability from cvelistv5 – Published: 2026-06-25 14:30 – Updated: 2026-06-25 15:05

Title

Nokogiri: XML::Schema on JRuby allows network requests when NONET is set, bypassing CVE-2020-26247

Summary

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, the NONET parse option, which Nokogiri turns on by default for Nokogiri::XML::Schema (see CVE-2020-26247), was not correctly enforced on the JRuby implementation. As a result, a schema parsed with default options could still cause external resources to be fetched over the network, potentially enabling SSRF or XXE attacks. This vulnerability is fixed in 1.19.4.

Severity

2.6 (Low)


                        
                          CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-178 - Improper Handling of Case Sensitivity
CWE-184 - Incomplete List of Disallowed Inputs
CWE-611 - Improper Restriction of XML External Entity Reference

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

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-57234",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-25T15:05:35.927298Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-25T15:05:42.484Z",
          "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, the NONET parse option, which Nokogiri turns on by default for Nokogiri::XML::Schema (see CVE-2020-26247), was not correctly enforced on the JRuby implementation. As a result, a schema parsed with default options could still cause external resources to be fetched over the network, potentially enabling SSRF or XXE attacks. This vulnerability is fixed in 1.19.4."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 2.6,
            "baseSeverity": "LOW",
            "confidentialityImpact": "LOW",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-178",
              "description": "CWE-178: Improper Handling of Case Sensitivity",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-184",
              "description": "CWE-184: Incomplete List of Disallowed Inputs",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-611",
              "description": "CWE-611: Improper Restriction of XML External Entity Reference",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-25T14:30:20.478Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-8678-w3jw-xfc2",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-8678-w3jw-xfc2"
        }
      ],
      "source": {
        "advisory": "GHSA-8678-w3jw-xfc2",
        "discovery": "UNKNOWN"
      },
      "title": "Nokogiri: XML::Schema on JRuby allows network requests when NONET is set, bypassing CVE-2020-26247"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-57234",
    "datePublished": "2026-06-25T14:30:20.478Z",
    "dateReserved": "2026-06-24T02:21:33.812Z",
    "dateUpdated": "2026-06-25T15:05:42.484Z",
    "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-8678-W3JW-XFC2

Summary

Severity

Mitigation

References

Credit

CVE-2026-57234 (GCVE-0-2026-57234)

Tags

Sightings

Nomenclature