Authentication Bypass by Assumed-Immutable Data Affecting microsoft.aspnetcore.authentication.negotiate package, versions [8.0.0,8.0.29)[9.0.0,9.0.18)[10.0.0,10.0.10)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DOTNET-MICROSOFTASPNETCOREAUTHENTICATIONNEGOTIATE-17979620
- published15 Jul 2026
- disclosed15 Jul 2026
- creditPham Quang Minh
Introduced: 15 Jul 2026
CVE-2026-47303 (opens in a new tab)How to fix?
Upgrade Microsoft.AspNetCore.Authentication.Negotiate to version 8.0.29, 9.0.18, 10.0.10 or higher.
Overview
Affected versions of this package are vulnerable to Authentication Bypass by Assumed-Immutable Data via improper parsing in the ASP.NET Core Negotiate authentication handler. An attacker can elevate privileges by supplying crafted authentication data that is parsed incorrectly, allowing authentication or authorization decisions to be made based on improperly interpreted input.