CVE-2024-51987
MEDIUMHTTP Client uses incorrect token after refresh in Duende.AccessTokenManagement.OpenIdConnect
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
Duende.AccessTokenManagement.OpenIdConnectReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
Description
Duende.AccessTokenManagement.OpenIdConnect is a set of .NET libraries that manage OAuth and OpenId Connect access tokens. HTTP Clients created by AddUserAccessTokenHttpClient may use a different user's access token after a token refresh occurs. This occurs because a refreshed token will be captured in pooled HttpClient instances, which may be used by a different user. Instead of using AddUserAccessTokenHttpClient to create an HttpClient that automatically adds a managed token to outgoing requests, you can use the HttpConext.GetUserAccessTokenAsync extension method or the IUserTokenManagementService.GetAccessTokenAsync method. This issue is fixed in Duende.AccessTokenManagement.OpenIdConnect 3.0.1. All users are advised to upgrade. There are no known workarounds for this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | Duende.AccessTokenManagement.OpenIdConnect | ≥ 3.0.0&&< 3.0.1 | 3.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Duende.AccessTokenManagement.OpenIdConnect. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update Duende.AccessTokenManagement.OpenIdConnect to 3.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-51987 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2024-51987 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2024-51987. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2024-51987 in your dependencies?
O3 detects CVE-2024-51987 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.