Summary
Servify-express rate limit issue
Workarounds
Users can mitigate the issue without upgrading by:
- Adding a
limitoption to the JSON parser - Implementing rate limiting at the application or reverse-proxy level
- Rejecting unusually large requests before parsing
- Using a reverse proxy (such as NGINX) to enforce maximum request body sizes
Impact
The Express server uses express.json() without a size limit, which can allow attackers to send extremely large request bodies. This may lead to excessive memory usage, degraded performance, or process crashes, resulting in a Denial of Service (DoS). Any application using the JSON parser without limits and exposed to untrusted clients is affected.
The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap. Typical impact: resource exhaustion leading to denial of service.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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This issue is not a flaw in Express itself but in configuration. Users should set a request-size limit when enabling the JSON body parser. For example:app.use(express.json({ limit: "100kb" }));
Frequently Asked Questions
- What is CVE-2025-67731? CVE-2025-67731 is a high-severity allocation of resources without limits or throttling vulnerability in servify-express (npm), affecting versions <= 1.1. It is fixed in 1.2. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
- Which versions of servify-express are affected by CVE-2025-67731? servify-express (npm) versions <= 1.1 is affected.
- Is there a fix for CVE-2025-67731? Yes. CVE-2025-67731 is fixed in 1.2. Upgrade to this version or later.
- Is CVE-2025-67731 exploitable, and should I be worried? Whether CVE-2025-67731 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-67731 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-67731? Upgrade
servify-expressto 1.2 or later.