CVE-2018-3738: Denial of Service in protobufjs

protobufjs Updated 02 Oct 2025

Summary

09/10/2018

Disclosed on

CVE-2018-3738

CVE

Yes i

Fix available

Moderate

Severity

5.5

CVSS Score

CVE-2018-3738: Denial of Service in protobufjs. Affects protobufjs across 2 version ranges.

< 5.0.3 >= 6.0.0, < 6.8.6

Fixed in 5.0.3 or 6.8.6, depending on the release line you run. How to fix ↓

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Background

protobufjs is an npm package that provides an implementation of the Protocol Buffers data interchange format. It allows developers to define the structure of their data using a language-agnostic interface and then generate code in various programming languages to serialize, deserialize, and manipulate the data. This package is widely used in applications that require efficient and platform-independent data serialization. However, versions of protobufjs before 5.0.3 and 6.8.6 are vulnerable to a regular expression denial of service (ReDoS) when parsing crafted invalid *.proto files.

Vulnerability Detail

The vulnerability in protobufjs arises from a lack of proper input validation when parsing *.proto files. An attacker can exploit this by providing a specially crafted invalid file that triggers a ReDoS attack. When the vulnerable version of protobufjs attempts to parse the malicious file, it gets stuck in an inefficient regular expression pattern matching process, leading to a denial of service condition. This can result in excessive CPU and memory usage, causing the application to become unresponsive or crash. The severity of this vulnerability is rated as MODERATE with a CVSS score of 5.5.

How To Fix

Latest published version: 8.8.1 as of 23 Oct 2026

npm install protobufjs@8.8.1

Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.

If you can't move to the latest

The minimum fixed version depends on the release line you run.

< 5.0.3 5.0.3
```
npm install protobufjs@5.0.3
```
>= 6.0.0, < 6.8.6 6.8.6
```
npm install protobufjs@6.8.6
```

Tip — Not sure which release line you're on? Vulert can find the fix for the version you are using. Scan free →

Workaround

There is no known workaround for this vulnerability. It is essential to update to the fixed versions mentioned above to mitigate the risk of a ReDoS attack.

Conclusion

The vulnerability in protobufjs versions before 5.0.3 and 6.8.6 can be exploited through crafted invalid *.proto files, leading to a denial of service condition. To mitigate this risk, it is crucial to update to the fixed versions mentioned above. For further support on vulnerability remediation, you can contact DevNack.com.

See every vulnerability recorded for protobufjs →

FAQ

What is protobufjs?

What is a regular expression denial of service (ReDoS) attack?

A regular expression denial of service (ReDoS) attack is a type of vulnerability where an attacker can exploit inefficient regular expressions to cause a denial of service condition. By providing specially crafted input, the attacker can trigger excessive CPU and memory usage, leading to application slowdown or crash.

What are the potential consequences of this vulnerability?

The potential consequences of this vulnerability include application unresponsiveness, increased CPU and memory usage, and possible application crashes. An attacker could exploit this vulnerability to disrupt the availability of the affected application.

How can I check if my application is affected by this vulnerability?

You can use Vulert's playground (https://vulert.com/scanner) to check if your application is affected by this vulnerability. Vulert monitors and alerts in real-time for open-source vulnerabilities using just the package-lock.json file, without requiring access to the code or installation.