CVE-2026-97151 Code injection in mammoth.js
Attackers can achieve code execution via prototype pollution in mammoth.js, and potentially read local files if external access is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-97151?
CVE-2026-97151 is a high-severity code injection vulnerability in mwilliamson mammoth.js, published on 24 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-1321
Which versions are affected by CVE-2026-97151?
How do I fix CVE-2026-97151?
No fix has been published for CVE-2026-97151 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-97151 being exploited?
There is no known exploitation of CVE-2026-97151 in the wild and no public exploit code.
Sources
Also known as GHSA-89qm-22qm-xf5h.