Mammoth is vulnerable to Directory Traversal
Versions of the package mammoth from 0.3.25 and before 1.11.0; versions of the package mammoth from 0.3.25 and before 1.11.0; versions of the package mammoth before 1.11.0; versions of the package org.zwobble.mammoth:mammoth before 1.11.0 are vulnerable to Directory Traversal due to the lack of path or file type validation when processing a docx file containing an image with an external link (r:link attribute instead of embedded r:embed). The library resolves the URI to a file path and after reading, the content is encoded as base64 and included in the HTML output as a data URI. An attacker can read arbitrary files on the system where the conversion is performed or cause an excessive resources consumption by crafting a docx file that links to special device files such as /dev/random or /dev/zero.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Java / Kotlin (Maven) | org.zwobble.mammoth:mammoth | < 1.11.0 | 1.11.0 |
| npm package | mammoth | >= 0.3.25, < 1.11.0 | 1.11.0 |
| .NET (NuGet) | Mammoth | < 1.11.0 | 1.11.0 |
| Python (PyPI) | mammoth | >= 0.3.25, < 1.11.0 | 1.11.0 |
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-11849
- https://github.com/mwilliamson/mammoth.js/commit/c54aaeb43a7941317c1f3c119ffa92090f988820
- https://gist.github.com/AudunWA/4d690d9ae5efdafe7cf71d9c2ee90a10
- https://github.com/mwilliamson/java-mammoth
- https://security.snyk.io/vuln/SNYK-DOTNET-MAMMOTH-13561968
- https://security.snyk.io/vuln/SNYK-JAVA-ORGZWOBBLEMAMMOTH-13561969
- https://security.snyk.io/vuln/SNYK-JS-MAMMOTH-13554470
- https://security.snyk.io/vuln/SNYK-PYTHON-MAMMOTH-13561967
- https://pypi.org/project/mammoth
- https://github.com/advisories/GHSA-rmjr-87wv-gf87
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:H- Weakness (CWE)
CWE-22- Platform
- Java / Kotlin (Maven), npm, .NET (NuGet), Python (PyPI)
- Package
org.zwobble.mammoth:mammoth, mammoth, Mammoth- Disclosed
- 17.10.2025
- Updated
- 11.10.2026 13:18
Sources and licenses
OSV / GitHub Advisory Database - GHSA-rmjr-87wv-gf87 - CC BY 4.0
OSV / GitHub Advisory Database - PYSEC-2026-1603 - PyPA Advisory Database; CC BY 4.0
Vulnerability history: Mammoth
All published vulnerabilities of this package (.NET (NuGet)), newest first. Shows whether this is a one-off slip or a package that needs watching.
This is the only known vulnerability of this package.
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