Vulnerability-Lookup

CVE-2026-83608 (GCVE-0-2026-83608)

Vulnerability from cvelistv5 – Published: 2026-09-01 14:27 – Updated: 2026-09-04 01:56

Title

xmldom: DocType `name` Injection Bypasses requireWellFormed

Summary

xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. Prior to @xmldom/xmldom versions 0.8.15 and 0.9.12, and in xmldom version 0.6.0 and earlier, the DOCUMENT_TYPE_NODE branch in lib/dom.js validates publicId, systemId, and internalSubset under requireWellFormed: true but emits DocumentType.name verbatim. A name containing > or whitespace can terminate the <!DOCTYPE ...> declaration and inject sibling markup; the value can be supplied through createDocumentType() on the 0.8.x and unscoped lines or through a direct DocumentType.name property write on every affected line. The default path and legacy creation-time behavior remain permissive, while the vulnerable strict path fails to enforce an XML Name. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; no fixed version is available for xmldom.

Severity

8.7 (High)


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

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-04 01:55 UTC

CWE

CWE-91 - XML Injection (aka Blind XPath Injection)

Assigner

GitHub_M mitre root

References

7 references

URL	Tags
https://github.com/xmldom/xmldom/security/advisor…	x_refsource_CONFIRM
https://github.com/xmldom/xmldom/pull/1071	x_refsource_MISC
https://github.com/xmldom/xmldom/pull/1072	x_refsource_MISC
https://github.com/xmldom/xmldom/commit/57aec90ac…	x_refsource_MISC
https://github.com/xmldom/xmldom/commit/85f12eb4d…	x_refsource_MISC
https://github.com/xmldom/xmldom/releases/tag/0.8.15	x_refsource_MISC
https://github.com/xmldom/xmldom/releases/tag/0.9.12	x_refsource_MISC

Impacted products

2 products

Vendor	Product	Version	CPE status
xmldom	xmldom	Affected: <= 0.6.0	guessed
@xmldom	xmldom	Affected: >= 0.9.0, < 0.9.12 Affected: >= 0.7.0, < 0.8.15	guessed

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            },
            {
              "name": "https://github.com/xmldom/xmldom/releases/tag/0.8.15",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/xmldom/xmldom/releases/tag/0.8.15"
            },
            {
              "name": "https://github.com/xmldom/xmldom/releases/tag/0.9.12",
              "tags": [
                "x_refsource_MISC"
              ],
              "url": "https://github.com/xmldom/xmldom/releases/tag/0.9.12"
            }
          ],
          "source": {
            "advisory": "GHSA-27p8-2357-5qqv",
            "discovery": "UNKNOWN"
          },
          "title": "xmldom: DocType `name` Injection Bypasses requireWellFormed"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-83608",
        "datePublished": "2026-09-01T14:27:26.057Z",
        "dateReserved": "2026-08-31T20:36:25.743Z",
        "dateUpdated": "2026-09-04T01:56:15.954Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}

FKIE_CVE-2026-83608

Vulnerability from fkie_nvd - Published: 2026-09-01 15:17 - Updated: 2026-09-08 21:11

Severity

8.7 (High) - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/xmldom/xmldom/commit/57aec90ac57b4408ae7c5d1746bf2a693b5ed90e
	security-advisories@github.com	https://github.com/xmldom/xmldom/commit/85f12eb4d14b44de33216cfb72b50af4d24e9fdd
	security-advisories@github.com	https://github.com/xmldom/xmldom/pull/1071
	security-advisories@github.com	https://github.com/xmldom/xmldom/pull/1072
	security-advisories@github.com	https://github.com/xmldom/xmldom/releases/tag/0.8.15
	security-advisories@github.com	https://github.com/xmldom/xmldom/releases/tag/0.9.12
	security-advisories@github.com	https://github.com/xmldom/xmldom/security/advisories/GHSA-27p8-2357-5qqv
	134c704f-9b21-4f2e-91b3-4a467353bcc0	https://github.com/xmldom/xmldom/security/advisories/GHSA-27p8-2357-5qqv

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "xmldom",
          "vendor": "xmldom",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c= 0.6.0"
            }
          ]
        },
        {
          "product": "xmldom",
          "vendor": "@xmldom",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.9.0, \u003c 0.9.12"
            },
            {
              "status": "affected",
              "version": "\u003e= 0.7.0, \u003c 0.8.15"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. Prior to @xmldom/xmldom versions 0.8.15 and 0.9.12, and in xmldom version 0.6.0 and earlier, the DOCUMENT_TYPE_NODE branch in lib/dom.js validates publicId, systemId, and internalSubset under requireWellFormed: true but emits DocumentType.name verbatim. A name containing \u003e or whitespace can terminate the \u003c!DOCTYPE ...\u003e declaration and inject sibling markup; the value can be supplied through createDocumentType() on the 0.8.x and unscoped lines or through a direct DocumentType.name property write on every affected line. The default path and legacy creation-time behavior remain permissive, while the vulnerable strict path fails to enforce an XML Name. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; no fixed version is available for xmldom."
    }
  ],
  "id": "CVE-2026-83608",
  "lastModified": "2026-09-08T21:11:31.703",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 8.7,
          "baseSeverity": "HIGH",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-83608",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-09-04T01:55:40.466309Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-09-01T15:17:38.800",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/xmldom/xmldom/commit/57aec90ac57b4408ae7c5d1746bf2a693b5ed90e"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/xmldom/xmldom/commit/85f12eb4d14b44de33216cfb72b50af4d24e9fdd"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/xmldom/xmldom/pull/1071"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/xmldom/xmldom/pull/1072"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/xmldom/xmldom/releases/tag/0.8.15"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/xmldom/xmldom/releases/tag/0.9.12"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/xmldom/xmldom/security/advisories/GHSA-27p8-2357-5qqv"
    },
    {
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "url": "https://github.com/xmldom/xmldom/security/advisories/GHSA-27p8-2357-5qqv"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-91"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Secondary"
    }
  ]
}

GHSA-27P8-2357-5QQV

Vulnerability from github – Published: 2026-09-08 21:02 – Updated: 2026-09-08 21:02

Summary

xmldom: DocType `name` Injection Bypasses requireWellFormed

Details

Summary

The @xmldom/xmldom serializer emits DocumentType.name verbatim into the <!DOCTYPE …> declaration with no well-formedness guard. GHSA-f6ww-3ggp-fr8h (CVE-2026-41674) hardened the serializer's requireWellFormed path for a DocumentType's sibling fields — publicId, systemId, and internalSubset — but it did not add any check for name. A > (or whitespace) in the name terminates the doctype declaration early, letting the remaining characters become sibling markup in the serialized output.

Because requireWellFormed: true — the recommended mitigation for the prior xmldom injection CVEs — performs no validation on the DocType name, this is a bypass of that control, in the same family as the open element-name (GHSA-w2rr-34g9-rvrj) and attribute-name (GHSA-4w3w-2rp5-g8jm) name-injection advisories.

Details

The serializer's DOCUMENT_TYPE_NODE case runs the requireWellFormed block only against publicId, systemId, and internalSubset, then pushes n.name directly into the buffer between the <!DOCTYPE prefix and the closing >:

0.9.x (v0.9.10, bb7a085): serializer DocType case, lib/dom.js#L3256-L3283 — the requireWellFormed block (#L3259-L3269) validates publicId/systemId/internalSubset but not name, which is emitted verbatim at #L3270.
0.8.x (v0.8.13, e5c1480): serializer DocType case, lib/dom.js#L1914-L1946 — same structure; name is emitted verbatim at #L1928.
unscoped xmldom (v0.6.0, c80a161): lib/dom.js#L1105 emits node.name verbatim; this line predates requireWellFormed, so there is no well-formedness path at all.

Enabling write paths

DocumentType.name is a plain, writable own-property, so the enabling vector differs by line:

0.9.x — createDocumentType() validates the name via validateQualifiedName (lib/dom.js#L925-L936, validation at #L926), so the deliverable vector is a direct property write (dt.name = 'html><script>…') to the unguarded own-property.
0.8.x — createDocumentType() does not validate the name (lib/dom.js#L456-L464), so the malicious name is reachable directly through createDocumentType() as well as via direct property write.
unscoped xmldom (<= 0.6.0) — createDocumentType() does not validate the name (lib/dom.js#L286), same as 0.8.x.

This is the same structural root cause the sibling name-injection advisories share: the serializer's requireWellFormed path validates content delimiters but no name field, and every name-like field is a plain writable property, so mutation / direct property-write bypasses any creation-time check.

Root Cause

The serializer's requireWellFormed DocType block checks publicId, systemId, and internalSubset (the fields hardened by GHSA-f6ww-3ggp-fr8h) but has no check for name.
DocumentType.name is a plain writable own-property; on 0.8.x and the unscoped package createDocumentType() does not validate it either.
The serializer emits name directly between the doctype delimiters: <!DOCTYPE ${name}…>.

Proof of Concept

Run against @xmldom/xmldom v0.9.10 (commit bb7a085):

const { DOMImplementation, XMLSerializer, DOMParser } = require('@xmldom/xmldom');

const impl = new DOMImplementation();
const serializer = new XMLSerializer();

// 0.9.x createDocumentType validates the name, so overwrite it via direct property write
const dt = impl.createDocumentType('html', '', '');
dt.name = 'html><script xmlns="http://www.w3.org/1999/xhtml">alert(1)</script';
const doc = impl.createDocument(null, 'r', dt);

const output = serializer.serializeToString(doc, { requireWellFormed: true });
console.log(output);
// Output: <!DOCTYPE html><script xmlns="http://www.w3.org/1999/xhtml">alert(1)</script><r/>
//
// requireWellFormed: true did NOT prevent the injection (no exception thrown).
// The injected <script> is well-formed XHTML that a browser would execute.

Confirmed runtime behavior:

0.9.x — createDocumentType() rejects the malicious name at creation (InvalidCharacterError); a direct write to dt.name bypasses that, and serializeToString(…, { requireWellFormed: true }) emits the breakout with no exception.
Re-parse confirmation — re-parsing the output shows the injected <script> is a real second top-level element originating entirely from the DocType name: the parser rejects it with HierarchyRequestError: Only one element can be added and only after doctype. A comment-injection variant (dt.name = 'html><r/>) re-parses cleanly and the injected comment node is enumerable, confirming the injected node is structurally live.
0.8.x (v0.8.13, e5c1480) — createDocumentType('html><script>…', '', '') accepts the malicious name directly (no creation-time validation), and serializeToString(doc, null, null, { requireWellFormed: true }) produces <!DOCTYPE html><script>alert(1)</script><r/> with no exception.

A browser reproduction does not apply: browsers keep DocumentType.name readonly, so the direct-write vector cannot be reproduced in a browser DOM. The injection is specific to xmldom exposing name as writable and serializing it without a guard.

Impact

Applications that build a DocumentType node with an attacker-influenced name — via direct property write on any affected line, or via createDocumentType() on 0.8.x and the unscoped package — and serialize the document are vulnerable to XML/markup injection:

XML structure injection — breaking out of the <!DOCTYPE …> declaration to inject arbitrary sibling elements, comments, or additional markup into the output.
XSS via XHTML — if the serialized output is served as XHTML or processed by a browser-based XML parser, an injected <script> element (in the XHTML namespace) executes.
requireWellFormed bypass — applications that adopted requireWellFormed: true as a mitigation for the prior injection CVEs (including the sibling DocType fields fixed by GHSA-f6ww-3ggp-fr8h) remain vulnerable through the DocType name.

Fix Applied

Under requireWellFormed, the serializer validates the DocType name as a well-formed XML Name and throws InvalidStateError when it is not — matching the sibling publicId/systemId/internalSubset checks. Non-breaking and opt-in; ships on both maintained versions. No creation-time change is made: 0.9.x already validates the name at createDocumentType, and the 0.8.x/unscoped creation gap cannot be closed without a breaking change, so it is left unfixed. See the XML Name production.

⚠ Opt-in required. Protection is not automatic. Existing serialization calls remain vulnerable unless { requireWellFormed: true } is explicitly passed. Applications that serialize untrusted DOM content should audit all serializeToString() call sites and add it.

Proof of Concept - fixed path

const { DOMImplementation, XMLSerializer } = require('@xmldom/xmldom');

const impl = new DOMImplementation();
const serializer = new XMLSerializer();

const dt = impl.createDocumentType('html', '', '');
dt.name = 'html><script xmlns="http://www.w3.org/1999/xhtml">alert(1)</script';
const doc = impl.createDocument(null, 'r', dt);

// Default path: the ill-formed name is still emitted verbatim (injection present).
console.log(serializer.serializeToString(doc));
// <!DOCTYPE html><script xmlns="http://www.w3.org/1999/xhtml">alert(1)</script><r/>

// Opt-in path: serialization throws instead of emitting the breakout.
serializer.serializeToString(doc, { requireWellFormed: true });
// throws InvalidStateError

Why the default stays verbatim

W3C DOM Parsing's require-well-formed flag defaults to false, and the browser XMLSerializer emits the name verbatim in that default mode. Unconditionally throwing would be an unjustified breaking change against that specified default, so the guard is opt-in behind { requireWellFormed: true }.

Residual limitation

The default serialization path still emits the ill-formed DocType name verbatim; protection applies only when requireWellFormed: true is passed. No creation-time validation is added for the DocType name: 0.9.x already validates at createDocumentType, and the 0.8.x/unscoped creation gap is left unfixed — it cannot be closed without a breaking change.

Severity

8.7 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.8.14"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@xmldom/xmldom"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.7.0"
            },
            {
              "fixed": "0.8.15"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.9.11"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@xmldom/xmldom"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.9.0"
            },
            {
              "fixed": "0.9.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "xmldom"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "0.6.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-83608"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-91"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-08T21:02:51Z",
    "nvd_published_at": "2026-09-01T15:17:38Z",
    "severity": "HIGH"
  },
  "details": "## Summary\n\nThe `@xmldom/xmldom` serializer emits `DocumentType.name` verbatim into the\n`\u003c!DOCTYPE \u2026\u003e` declaration with no well-formedness guard. GHSA-f6ww-3ggp-fr8h\n(CVE-2026-41674) hardened the serializer\u0027s `requireWellFormed` path for a\nDocumentType\u0027s sibling fields \u2014 `publicId`, `systemId`, and `internalSubset` \u2014\nbut it did **not** add any check for `name`. A `\u003e` (or whitespace) in the name\nterminates the doctype declaration early, letting the remaining characters\nbecome sibling markup in the serialized output.\n\nBecause `requireWellFormed: true` \u2014 the recommended mitigation for the prior\nxmldom injection CVEs \u2014 performs no validation on the DocType `name`, this is a\nbypass of that control, in the same family as the open element-name\n(GHSA-w2rr-34g9-rvrj) and attribute-name (GHSA-4w3w-2rp5-g8jm) name-injection advisories.\n\n## Details\n\nThe serializer\u0027s `DOCUMENT_TYPE_NODE` case runs the `requireWellFormed` block\nonly against `publicId`, `systemId`, and `internalSubset`, then pushes\n`n.name` directly into the buffer between the `\u003c!DOCTYPE ` prefix and the\nclosing `\u003e`:\n\n- 0.9.x (v0.9.10, `bb7a085`):\n  [serializer DocType case, `lib/dom.js#L3256-L3283`](https://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom.js#L3256-L3283)\n  \u2014 the `requireWellFormed` block ([#L3259-L3269](https://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom.js#L3259-L3269))\n  validates `publicId`/`systemId`/`internalSubset` but not `name`, which is\n  emitted verbatim at [#L3270](https://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom.js#L3270).\n- 0.8.x (v0.8.13, `e5c1480`):\n  [serializer DocType case, `lib/dom.js#L1914-L1946`](https://github.com/xmldom/xmldom/blob/e5c14802592685bb872c042c54c3f73758875c85/lib/dom.js#L1914-L1946)\n  \u2014 same structure; `name` is emitted verbatim at [#L1928](https://github.com/xmldom/xmldom/blob/e5c14802592685bb872c042c54c3f73758875c85/lib/dom.js#L1928).\n- unscoped `xmldom` (v0.6.0, `c80a161`):\n  [`lib/dom.js#L1105`](https://github.com/xmldom/xmldom/blob/c80a161172cc4d8733583bf0cf59abfa589f6d9e/lib/dom.js#L1105)\n  emits `node.name` verbatim; this line predates `requireWellFormed`, so there\n  is no well-formedness path at all.\n\n### Enabling write paths\n\n`DocumentType.name` is a plain, writable own-property, so the enabling vector\ndiffers by line:\n\n- **0.9.x** \u2014 `createDocumentType()` validates the name via\n  `validateQualifiedName` ([`lib/dom.js#L925-L936`](https://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom.js#L925-L936),\n  validation at [#L926](https://github.com/xmldom/xmldom/blob/bb7a085dc5ba1eea3212388509b97bb4b4af32b9/lib/dom.js#L926)),\n  so the deliverable vector is a **direct property write**\n  (`dt.name = \u0027html\u003e\u003cscript\u003e\u2026\u0027`) to the unguarded own-property.\n- **0.8.x** \u2014 `createDocumentType()` does **not** validate the name\n  ([`lib/dom.js#L456-L464`](https://github.com/xmldom/xmldom/blob/e5c14802592685bb872c042c54c3f73758875c85/lib/dom.js#L456-L464)),\n  so the malicious name is reachable directly through `createDocumentType()` as\n  well as via direct property write.\n- **unscoped `xmldom` (\u003c= 0.6.0)** \u2014 `createDocumentType()` does not validate\n  the name ([`lib/dom.js#L286`](https://github.com/xmldom/xmldom/blob/c80a161172cc4d8733583bf0cf59abfa589f6d9e/lib/dom.js#L286)),\n  same as 0.8.x.\n\nThis is the same structural root cause the sibling name-injection advisories\nshare: the serializer\u0027s `requireWellFormed` path validates content delimiters\nbut no name field, and every name-like field is a plain writable property, so\nmutation / direct property-write bypasses any creation-time check.\n\n### Root Cause\n\n1. The serializer\u0027s `requireWellFormed` DocType block checks `publicId`,\n   `systemId`, and `internalSubset` (the fields hardened by GHSA-f6ww-3ggp-fr8h)\n   but has no check for `name`.\n2. `DocumentType.name` is a plain writable own-property; on 0.8.x and the\n   unscoped package `createDocumentType()` does not validate it either.\n3. The serializer emits `name` directly between the doctype delimiters:\n   `\u003c!DOCTYPE ${name}\u2026\u003e`.\n\n## Proof of Concept\n\nRun against `@xmldom/xmldom` v0.9.10 (commit `bb7a085`):\n\n```javascript\nconst { DOMImplementation, XMLSerializer, DOMParser } = require(\u0027@xmldom/xmldom\u0027);\n\nconst impl = new DOMImplementation();\nconst serializer = new XMLSerializer();\n\n// 0.9.x createDocumentType validates the name, so overwrite it via direct property write\nconst dt = impl.createDocumentType(\u0027html\u0027, \u0027\u0027, \u0027\u0027);\ndt.name = \u0027html\u003e\u003cscript xmlns=\"http://www.w3.org/1999/xhtml\"\u003ealert(1)\u003c/script\u0027;\nconst doc = impl.createDocument(null, \u0027r\u0027, dt);\n\nconst output = serializer.serializeToString(doc, { requireWellFormed: true });\nconsole.log(output);\n// Output: \u003c!DOCTYPE html\u003e\u003cscript xmlns=\"http://www.w3.org/1999/xhtml\"\u003ealert(1)\u003c/script\u003e\u003cr/\u003e\n//\n// requireWellFormed: true did NOT prevent the injection (no exception thrown).\n// The injected \u003cscript\u003e is well-formed XHTML that a browser would execute.\n```\n\nConfirmed runtime behavior:\n\n- **0.9.x** \u2014 `createDocumentType()` rejects the malicious name at creation\n  (`InvalidCharacterError`); a direct write to `dt.name` bypasses that, and\n  `serializeToString(\u2026, { requireWellFormed: true })` emits the breakout with no\n  exception.\n- **Re-parse confirmation** \u2014 re-parsing the output shows the injected\n  `\u003cscript\u003e` is a real second top-level element originating entirely from the\n  DocType name: the parser rejects it with\n  `HierarchyRequestError: Only one element can be added and only after doctype`.\n  A comment-injection variant (`dt.name = \u0027html\u003e\u003c!--INJECTED--\u0027`, output\n  `\u003c!DOCTYPE html\u003e\u003c!--INJECTED--\u003e\u003cr/\u003e`) re-parses cleanly and the injected\n  comment node is enumerable, confirming the injected node is structurally live.\n- **0.8.x** (v0.8.13, `e5c1480`) \u2014 `createDocumentType(\u0027html\u003e\u003cscript\u003e\u2026\u0027, \u0027\u0027, \u0027\u0027)`\n  accepts the malicious name directly (no creation-time validation), and\n  `serializeToString(doc, null, null, { requireWellFormed: true })` produces\n  `\u003c!DOCTYPE html\u003e\u003cscript\u003ealert(1)\u003c/script\u003e\u003cr/\u003e` with no exception.\n\nA browser reproduction does not apply: browsers keep `DocumentType.name`\n`readonly`, so the direct-write vector cannot be reproduced in a browser DOM.\nThe injection is specific to xmldom exposing `name` as writable and serializing\nit without a guard.\n\n## Impact\n\nApplications that build a `DocumentType` node with an attacker-influenced\n`name` \u2014 via direct property write on any affected line, or via\n`createDocumentType()` on 0.8.x and the unscoped package \u2014 and serialize the\ndocument are vulnerable to XML/markup injection:\n\n- **XML structure injection** \u2014 breaking out of the `\u003c!DOCTYPE \u2026\u003e` declaration\n  to inject arbitrary sibling elements, comments, or additional markup into the\n  output.\n- **XSS via XHTML** \u2014 if the serialized output is served as XHTML or processed\n  by a browser-based XML parser, an injected `\u003cscript\u003e` element (in the XHTML\n  namespace) executes.\n- **requireWellFormed bypass** \u2014 applications that adopted\n  `requireWellFormed: true` as a mitigation for the prior injection CVEs\n  (including the sibling DocType fields fixed by GHSA-f6ww-3ggp-fr8h) remain\n  vulnerable through the DocType `name`.\n\n## Fix Applied\n\nUnder `requireWellFormed`, the serializer validates the DocType `name` as a well-formed XML\n`Name` and throws `InvalidStateError` when it is not \u2014 matching the sibling\n`publicId`/`systemId`/`internalSubset` checks. Non-breaking and opt-in; ships on both maintained versions. No\ncreation-time change is made: 0.9.x already validates the name at `createDocumentType`, and the\n0.8.x/unscoped creation gap cannot be closed without a breaking change, so it is left\nunfixed. See the [XML `Name` production](https://www.w3.org/TR/xml/#NT-Name).\n\u003e **\u26a0 Opt-in required.** Protection is not automatic. Existing serialization calls remain\n\u003e vulnerable unless `{ requireWellFormed: true }` is explicitly passed. Applications that\n\u003e serialize untrusted DOM content should audit all `serializeToString()` call sites and add it.\n\n### Proof of Concept - fixed path\n\n```javascript\nconst { DOMImplementation, XMLSerializer } = require(\u0027@xmldom/xmldom\u0027);\n\nconst impl = new DOMImplementation();\nconst serializer = new XMLSerializer();\n\nconst dt = impl.createDocumentType(\u0027html\u0027, \u0027\u0027, \u0027\u0027);\ndt.name = \u0027html\u003e\u003cscript xmlns=\"http://www.w3.org/1999/xhtml\"\u003ealert(1)\u003c/script\u0027;\nconst doc = impl.createDocument(null, \u0027r\u0027, dt);\n\n// Default path: the ill-formed name is still emitted verbatim (injection present).\nconsole.log(serializer.serializeToString(doc));\n// \u003c!DOCTYPE html\u003e\u003cscript xmlns=\"http://www.w3.org/1999/xhtml\"\u003ealert(1)\u003c/script\u003e\u003cr/\u003e\n\n// Opt-in path: serialization throws instead of emitting the breakout.\nserializer.serializeToString(doc, { requireWellFormed: true });\n// throws InvalidStateError\n```\n\n### Why the default stays verbatim\n\nW3C DOM Parsing\u0027s require-well-formed flag defaults to false, and the browser\n`XMLSerializer` emits the name verbatim in that default mode. Unconditionally\nthrowing would be an unjustified breaking change against that specified default,\nso the guard is opt-in behind `{ requireWellFormed: true }`.\n\n### Residual limitation\n\nThe default serialization path still emits the ill-formed DocType `name`\nverbatim; protection applies only when `requireWellFormed: true` is passed. No\ncreation-time validation is added for the DocType `name`: 0.9.x already validates\nat `createDocumentType`, and the 0.8.x/unscoped creation gap is left unfixed \u2014 it\ncannot be closed without a breaking change.",
  "id": "GHSA-27p8-2357-5qqv",
  "modified": "2026-09-08T21:02:51Z",
  "published": "2026-09-08T21:02:51Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/xmldom/xmldom/security/advisories/GHSA-27p8-2357-5qqv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-83608"
    },
    {
      "type": "WEB",
      "url": "https://github.com/xmldom/xmldom/pull/1071"
    },
    {
      "type": "WEB",
      "url": "https://github.com/xmldom/xmldom/pull/1072"
    },
    {
      "type": "WEB",
      "url": "https://github.com/xmldom/xmldom/commit/57aec90ac57b4408ae7c5d1746bf2a693b5ed90e"
    },
    {
      "type": "WEB",
      "url": "https://github.com/xmldom/xmldom/commit/85f12eb4d14b44de33216cfb72b50af4d24e9fdd"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/xmldom/xmldom"
    },
    {
      "type": "WEB",
      "url": "https://github.com/xmldom/xmldom/releases/tag/0.8.15"
    },
    {
      "type": "WEB",
      "url": "https://github.com/xmldom/xmldom/releases/tag/0.9.12"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "xmldom: DocType `name` Injection Bypasses requireWellFormed"
}

MSRC_CVE-2026-83608

Vulnerability from csaf_microsoft - Published: 2026-09-06 15:09 - Updated: 2026-09-09 01:50

Summary

xmldom: DocType `name` Injection Bypasses requireWellFormed

Scope

1 vulnerability in this advisory, including CVE-2026-83608.

CVE-2026-83608

Known not affected: 1 product

Open the full advisory

RHSA-2026:69248

Vulnerability from csaf_redhat - Published: 2026-09-21 07:52 - Updated: 2026-09-22 09:44

Summary

Red Hat Security Advisory: Red Hat Developer Hub 1.9.9 release.

Severity

Important

Scope

30 vulnerabilities in this advisory, including CVE-2026-83608.

CVE-2026-83608

A flaw was found in xmldom, a JavaScript module for parsing and serializing XML. A remote attacker can exploit this vulnerability by providing a specially crafted `DocumentType.name` containing characters like `>` or whitespace. This bypasses the `requireWellFormed` validation, allowing the injection of arbitrary XML markup. Such injection can lead to unintended modifications of the XML document structure, potentially resulting in arbitrary code execution or information disclosure within applications that process the affected XML.

3.1 (Low)


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

Fixed: 1 product Known not affected: 2 products

https://access.redhat.com/errata/RHSA-2026:69248

Open the full advisory

UBUNTU-CVE-2026-83608 (CVE-2026-83608)

Vulnerability from osv_ubuntu – Published: 2026-09-01 15:17 – Updated: 2026-09-16 11:43 – Source website

Details

Severity

8.7 (High)


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

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-83608	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-83608	REPORT
	https://github.com/xmldom/xmldom/security/advisor…	REPORT
	https://github.com/xmldom/xmldom/pull/1071	REPORT
	https://github.com/xmldom/xmldom/pull/1072	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-xmldom",
            "binary_version": "0.1.27+ds-1+deb10u2build0.20.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "node-xmldom",
        "purl": "pkg:deb/ubuntu/node-xmldom@0.1.27+ds-1+deb10u2build0.20.04.1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.1.27+ds-1",
        "0.1.27+ds-1+deb10u2build0.20.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-xmldom",
            "binary_version": "0.7.5-1ubuntu0.22.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "node-xmldom",
        "purl": "pkg:deb/ubuntu/node-xmldom@0.7.5-1ubuntu0.22.04.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.5.0-1",
        "0.7.3-1",
        "0.7.5-1",
        "0.7.5-1ubuntu0.22.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-xmldom",
            "binary_version": "0.8.6-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "node-xmldom",
        "purl": "pkg:deb/ubuntu/node-xmldom@0.8.6-1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.8.6-1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "node-xmldom",
            "binary_version": "0.9.8-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "node-xmldom",
        "purl": "pkg:deb/ubuntu/node-xmldom@0.9.8-2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.6-1",
        "0.9.8-1",
        "0.9.8-2"
      ]
    }
  ],
  "aliases": [],
  "details": "xmldom is a pure JavaScript W3C standard-based (XML DOM Level 2 Core) DOMParser and XMLSerializer module. Prior to @xmldom/xmldom versions 0.8.15 and 0.9.12, and in xmldom version 0.6.0 and earlier, the DOCUMENT_TYPE_NODE branch in lib/dom.js validates publicId, systemId, and internalSubset under requireWellFormed: true but emits DocumentType.name verbatim. A name containing \u003e or whitespace can terminate the \u003c!DOCTYPE ...\u003e declaration and inject sibling markup; the value can be supplied through createDocumentType() on the 0.8.x and unscoped lines or through a direct DocumentType.name property write on every affected line. The default path and legacy creation-time behavior remain permissive, while the vulnerable strict path fails to enforce an XML Name. This issue is fixed in @xmldom/xmldom versions 0.8.15 and 0.9.12; no fixed version is available for xmldom.",
  "id": "UBUNTU-CVE-2026-83608",
  "modified": "2026-09-16T11:43:10Z",
  "published": "2026-09-01T15:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-83608"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-83608"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/xmldom/xmldom/security/advisories/GHSA-27p8-2357-5qqv"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/xmldom/xmldom/pull/1071"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/xmldom/xmldom/pull/1072"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-83608"
  ]
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-83608 (GCVE-0-2026-83608)

FKIE_CVE-2026-83608

GHSA-27P8-2357-5QQV

Summary

Details

Enabling write paths

Root Cause

Proof of Concept

Impact

Fix Applied

Proof of Concept - fixed path

Why the default stays verbatim

Residual limitation

MSRC_CVE-2026-83608

RHSA-2026:69248

UBUNTU-CVE-2026-83608 (CVE-2026-83608)

Tags

Sightings

Nomenclature

Related by attack behaviour