Summary
Low severity vulnerability that affects Gw2Sharp
Leaking cached authenticated requests
Workarounds
For version 0.3.0 and lower, you can use one separate instance of MemoryCacheMethod per Gw2WebApiClient if you need to use it.
For more information
If you have any questions or comments about this advisory, you can open an issue in the Gw2Sharp repository or contact me on Discord.
Impact
If you've been using one MemoryCacheMethod object in multiple instances of Gw2WebApiClient and are requesting authenticated endpoints with different access tokens, then you are likely to run into this bug.
When using an instance of MemoryCacheMethod and using it with multiple instances of Gw2WebApiClient, there's a possibility that cached authenticated responses are leaking to another request to the same endpoint, but with a different Guild Wars 2 access token. The latter request wouldn't start however, and would return the first cached response immediately. This means that the second response (or later responses) may contain the same data as the first response, therefore leaking data from another authenticated endpoint.
The occurence of this is limited however. The Guild Wars 2 API doesn't use the Expires header on most (if not all) authenticated endpoints. This header is checked when caching responses. If this header isn't available, the response isn't cached at all. You should still update to at least version 0.3.1 in order to be certain that it won't happen.
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 bug has been fixed in version 0.3.1. When using an authenticated endpoint, it will prepend the SHA-1 hash of the access token to the cache id.
Frequently Asked Questions
- What is GHSA-4VR3-9V7H-5F8V? GHSA-4VR3-9V7H-5F8V is a low-severity security vulnerability in Gw2Sharp (nuget), affecting versions < 0.3.1. It is fixed in 0.3.1.
- Which versions of Gw2Sharp are affected by GHSA-4VR3-9V7H-5F8V? Gw2Sharp (nuget) versions < 0.3.1 is affected.
- Is there a fix for GHSA-4VR3-9V7H-5F8V? Yes. GHSA-4VR3-9V7H-5F8V is fixed in 0.3.1. Upgrade to this version or later.
- Is GHSA-4VR3-9V7H-5F8V exploitable, and should I be worried? Whether GHSA-4VR3-9V7H-5F8V 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-4VR3-9V7H-5F8V 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-4VR3-9V7H-5F8V? Upgrade
Gw2Sharpto 0.3.1 or later.