{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-97151", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "state": "PUBLISHED", "assignerShortName": "mitre", "dateReserved": "2026-09-24T03:08:15.164Z", "datePublished": "2026-09-24T03:08:15.523Z", "dateUpdated": "2026-09-24T03:08:15.523Z"}, "containers": {"cna": {"affected": [{"collectionURL": "https://registry.npmjs.org", "defaultStatus": "unaffected", "modules": ["docx styles reader"], "packageName": "mammoth", "packageURL": "pkg:npm/mammoth", "product": "mammoth.js", "programFiles": ["lib/docx/styles-reader.js"], "programRoutines": [{"name": "readStylesXml"}], "repo": "https://github.com/mwilliamson/mammoth.js", "vendor": "mwilliamson", "versions": [{"lessThan": "1.12.2", "status": "affected", "version": "0", "versionType": "semver"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "The prototype pollution itself requires no particular configuration. The less common externalFileAccess bypass additionally requires the application to convert more than one document within the same process and to return the converted HTML to the party supplying the documents.<br>"}], "value": "The prototype pollution itself requires no particular configuration. The less common externalFileAccess bypass additionally requires the application to convert more than one document within the same process and to return the converted HTML to the party supplying the documents."}], "descriptions": [{"lang": "en", "value": "mammoth (aka mammoth.js) before 1.12.2 is vulnerable to prototype pollution when reading the styles defined in a document. Converting a crafted .docx file allows an attacker to add arbitrary properties to Object.prototype. In 1.11.0 through 1.12.1, applications that convert further documents in the same process and return the converted HTML can also disclose the contents of local server files (to the party supplying the documents) by setting externalFileAccess to true."}], "metrics": [{"cvssV4_0": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "baseScore": 8.4, "baseSeverity": "HIGH", "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:P/PR:N/UI:N/VC:H/VI:L/VA:H/SC:N/SI:N/SA:N", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-1321", "description": "CWE-1321 Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-09-24T03:08:15.523Z"}, "references": [{"tags": ["release-notes", "vendor-advisory"], "url": "https://raw.githubusercontent.com/mwilliamson/mammoth.js/master/NEWS"}, {"tags": ["product"], "url": "https://www.npmjs.com/package/mammoth"}, {"tags": ["patch"], "url": "https://github.com/mwilliamson/mammoth.js/commit/31f0c370be4b95ac4fa285fea3be970606735f16"}, {"tags": ["patch"], "url": "https://github.com/mwilliamson/mammoth.js/commit/2888fa158d67c1419199f152326e12a05618b53e"}], "solutions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "Upgrade to mammoth 1.12.2 or later.<br>"}], "value": "Upgrade to mammoth 1.12.2 or later."}], "x_generator": {"engine": "CVE-Request-form 0.0.1"}}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://registry.npmjs.org", "defaultStatus": "unaffected", "modules": ["docx styles reader"], "packageName": "mammoth", "packageURL": "pkg:npm/mammoth", "product": "mammoth.js", "programFiles": ["lib/docx/styles-reader.js"], "programRoutines": [{"name": "readStylesXml"}], "repo": "https://github.com/mwilliamson/mammoth.js", "vendor": "mwilliamson", "versions": [{"lessThan": "1.12.2", "status": "affected", "version": "0", "versionType": "semver"}]}], "source": "cve@mitre.org"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "mammoth (aka mammoth.js) before 1.12.2 is vulnerable to prototype pollution when reading the styles defined in a document. Converting a crafted .docx file allows an attacker to add arbitrary properties to Object.prototype. In 1.11.0 through 1.12.1, applications that convert further documents in the same process and return the converted HTML can also disclose the contents of local server files (to the party supplying the documents) by setting externalFileAccess to true."}], "id": "CVE-2026-97151", "lastModified": "2026-09-24T04:18:06.027", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.4, "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:P/PR:N/UI:N/VC:H/VI:L/VA:H/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": "HIGH", "vulnConfidentialityImpact": "HIGH", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "cve@mitre.org", "type": "Secondary"}]}, "published": "2026-09-24T04:18:06.027", "references": [{"source": "cve@mitre.org", "url": "https://github.com/mwilliamson/mammoth.js/commit/2888fa158d67c1419199f152326e12a05618b53e"}, {"source": "cve@mitre.org", "url": "https://github.com/mwilliamson/mammoth.js/commit/31f0c370be4b95ac4fa285fea3be970606735f16"}, {"source": "cve@mitre.org", "url": "https://raw.githubusercontent.com/mwilliamson/mammoth.js/master/NEWS"}, {"source": "cve@mitre.org", "url": "https://www.npmjs.com/package/mammoth"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1321"}], "source": "cve@mitre.org", "type": "Primary"}]}

{}

{"created": "2026-09-24T05:30:05.810606+00:00", "title": "Prototype Pollution in mammoth.js via Malicious DOCX", "updated": "2026-09-24T05:30:05.810620+00:00", "vendors": []}