Summary
Microsoft Security Advisory CVE-2026-88092 - ASP.NET Core Security Feature Bypass Vulnerability
Advisory details
Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.Server.Kestrel.Core. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
An aborted Kestrel HTTP/1 connection can reparse unread request-body bytes as another request, creating a request-smuggling or desynchronization path.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/472
CVSS Details
- Version: 3.1
- Severity: Critical
- Score: 9.4
- Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L - Weakness: CWE-444 (Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling'))
Affected Platforms
- Platforms: Windows, Linux, macOS
- Architectures: All
Affected Packages
The vulnerability affects Microsoft .NET projects that use an affected package version listed below.
References
Related vulnerabilities
All Supply chain →- CRITICALCVE-2026-70188
Microsoft Security Advisory CVE-2026-70188 - ASP.NET Core Security Feature Bypass Vulnerability
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Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization