CVE Catalog

CVE-2026-97151

HighCVSS 8.4
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.36%

27th percentile - higher than 27% of all known CVEs

Summary

mammoth (aka mammoth.js) before 1.12.2 is vulnerable to prototype pollution when reading styles defined in a document. Converting a crafted .docx file allows an attacker to add arbitrary properties to Object.prototype, and in versions 1.11.0 through 1.12.1 it can also disclose local server file contents when externalFileAccess is set to true.

Risk Assessment

An attacker can inject properties into the object prototype, potentially causing unexpected application behavior and, in some configurations, disclosure of server file contents.

Recommendation

Update the mammoth library to version 1.12.2 or later and avoid setting externalFileAccess to true when converting untrusted documents.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS