Summary
Web Push Denial of Service via malicious Web Push endpoint
Prior to version 0.10.3, the built-in clients of the web-push crate eagerly allocated memory based on the Content-Length header returned by the Web Push endpoint. Malicious Web Push endpoints could return a large Content-Length without ever having to send as much data, leading to denial of service by memory exhaustion.
Services providing Web Push notifications typically allow the user to register an arbitrary endpoint, so the endpoint should not be trusted.
The fixed version 0.10.3 now limits the amount of memory it will allocate for each response, limits the amount of data it will read from the endpoint, and returns an error if the endpoint sends too much data.
As before, it is recommended that services add a timeout for each request to Web Push endpoints.
Impact
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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Frequently Asked Questions
- What is GHSA-FC83-9JWQ-GC2M? GHSA-FC83-9JWQ-GC2M is a medium-severity allocation of resources without limits or throttling vulnerability in web-push (rust), affecting versions < 0.10.4. It is fixed in 0.10.4. The application allocates resources such as memory, threads, or file descriptors based on untrusted input without enforcing a cap.
- Which versions of web-push are affected by GHSA-FC83-9JWQ-GC2M? web-push (rust) versions < 0.10.4 is affected.
- Is there a fix for GHSA-FC83-9JWQ-GC2M? Yes. GHSA-FC83-9JWQ-GC2M is fixed in 0.10.4. Upgrade to this version or later.
- Is GHSA-FC83-9JWQ-GC2M exploitable, and should I be worried? Whether GHSA-FC83-9JWQ-GC2M 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 GHSA-FC83-9JWQ-GC2M 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 GHSA-FC83-9JWQ-GC2M? Upgrade
web-pushto 0.10.4 or later.