mwilliamson mammoth.js up to 1.12.1 Document Style Processing externalFileAccess prototype pollution

CVSS Meta Temp Score
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CTI Interest Score
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6.0$0-$5k1.22

Summaryinfo

A vulnerability classified as critical was found in mwilliamson mammoth.js up to 1.12.1. Affected is an unknown function of the component Document Style Processing. Executing a manipulation of the argument externalFileAccess can lead to prototype pollution. This vulnerability is handled as CVE-2026-97151. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in mwilliamson mammoth.js up to 1.12.1. This vulnerability affects an unknown function of the component Document Style Processing. The manipulation of the argument externalFileAccess with an unknown input leads to a prototype pollution vulnerability. The CWE definition for the vulnerability is CWE-1321. The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at raw.githubusercontent.com. This vulnerability was named CVE-2026-97151 since 09/24/2026. The exploitation appears to be easy. The attack can be initiated remotely. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.

Upgrading to version 1.12.2 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Prototype pollution
CWE: CWE-1321 / CWE-94 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: mammoth.js 1.12.2

Timelineinfo

09/24/2026 Advisory disclosed
09/24/2026 +0 days CVE reserved
09/24/2026 +0 days VulDB entry created
09/24/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: raw.githubusercontent.com
Status: Confirmed

CVE: CVE-2026-97151 (🔒)
GCVE (CVE): GCVE-0-2026-97151
GCVE (VulDB): GCVE-100-409276

Entryinfo

Created: 09/24/2026 05:41
Changes: 09/24/2026 05:41 (30), 09/24/2026 05:42 (38)
Complete: 🔍
Cache ID: 216::103

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