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.