CVE-2021-25953: Prototype Pollution in putil-merge
Summary
CVE-2021-25953: Prototype Pollution in putil-merge. Affects putil-merge versions >= 1.0.0, < 3.7.0. Fixed in 3.7.0. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
putil-merge is an npm package that provides utility functions for merging JavaScript objects. It is commonly used in web applications to combine and manipulate data objects. However, versions 1.0.0 through 3.6.6 of putil-merge are vulnerable to prototype pollution.
Vulnerability Detail
The vulnerability in putil-merge allows an attacker to perform prototype pollution, which can lead to a denial of service and potentially remote code execution. Prototype pollution occurs when an attacker can modify the prototype of an object, allowing them to inject malicious properties or modify existing ones. In the case of putil-merge, an attacker can manipulate the merging process to modify the target object's prototype, leading to unexpected behavior and potential security issues.
How To Fix
Latest published version: 3.13.0 as of 23 Oct 2026
npm install putil-merge@3.13.0Upgrading to it may include breaking changes; the version below is the minimum fixed release for this vulnerability.
If you need the minimum change
3.7.0
This is the first release that contains the fix.
npm install putil-merge@3.7.0Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If you are unable to immediately update to the fixed version, a temporary workaround is to avoid using putil-merge or any code that relies on it until the vulnerability is resolved. Instead, consider using alternative libraries or implementing custom merging functions that do not suffer from prototype pollution.
Conclusion
The prototype pollution vulnerability in putil-merge can have severe consequences, including denial of service and potential remote code execution. It is crucial to update to the fixed version (3.7.0 or later) or apply the recommended workarounds to mitigate the risk. For further assistance and support in vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for putil-merge →
FAQ
Prototype pollution is a vulnerability that allows an attacker to modify the prototype of an object, leading to unexpected behavior and potential security issues.
The prototype pollution vulnerability in putil-merge can result in a denial of service and potentially remote code execution. An attacker could manipulate the merging process to inject malicious properties or modify existing ones, leading to unexpected behavior and potential security breaches.
Versions 1.0.0 through 3.6.6 of putil-merge are affected by this vulnerability. It is recommended to update to version 3.7.0 or later to mitigate the risk.
To update putil-merge to the fixed version (3.7.0 or later), run the following command in your project directory: npm install putil-merge@latest
If you are unable to immediately update to the fixed version, a temporary workaround is to avoid using putil-merge or any code that relies on it until the vulnerability is resolved. Consider using alternative libraries or implementing custom merging functions that do not suffer from prototype pollution.
Related vulnerabilities
Recent vulnerabilities recorded for putil-merge.
