CVE-2023-36435 Microsoft QUIC Denial of Service Vulnerability

High 7.5 Published 10 Oct 2023 Updated 14 Apr 2025

Attackers can cause a denial of service in Microsoft QUIC implementations affecting Windows and .NET, requiring patches.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2023-36435?

CVE-2023-36435 is a high-severity denial of service vulnerability in Microsoft .Net, published on 10 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Microsoft QUIC Denial of Service Vulnerability

Weakness: CWE-400

Which versions are affected by CVE-2023-36435?

6 open source packages ship an affected version, including Microsoft.Native.Quic.MsQuic.OpenSSL, dotnet and dotnet-sdk. It affects 4 products.

Package	Affected	Fixed in
`Microsoft.Native.Quic.MsQuic.OpenSSL` NuGet	All versions	`2.2.3`
`Microsoft.Native.Quic.MsQuic.OpenSSL` NuGet	All versions	`2.2.3`
`dotnet` Bitnami	From `7.0.0`	`7.0.13`
`dotnet-sdk` Bitnami	From `7.0.0`	`7.0.13`
`Microsoft.Native.Quic.MsQuic.Schannel` NuGet	All versions	`2.2.3`
`Microsoft.Native.Quic.MsQuic.Schannel` NuGet	All versions	`2.2.3`

Products include Microsoft .Net, Microsoft Windows 11 21h2, Microsoft Windows 11 22h2, Microsoft Windows Server 2022.

How do I fix CVE-2023-36435?

Upgrade Microsoft.Native.Quic.MsQuic.OpenSSL to 2.2.3 or later.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2023-36435 being exploited?

There is no known exploitation of CVE-2023-36435 in the wild and no public exploit code.

All Microsoft .Net vulnerabilities

Sources

Also known as BIT-dotnet-2023-36435, BIT-dotnet-sdk-2023-36435, GHSA-fr44-546p-7xcp.