CVE-2026-62815 Microsoft QUIC Remote Code Execution Vulnerability
An unauthorized attacker can execute code over the network via a use-after-free flaw in the Microsoft QUIC implementation on Windows.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-62815?
CVE-2026-62815 is a critical use after free vulnerability in Microsoft Windows 11 23h2, published on 11 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
Weakness: CWE-416
Which versions are affected by CVE-2026-62815?
8 open source packages ship an affected version, including Microsoft.Native.Quic.MsQuic.OpenSSL and Microsoft.Native.Quic.MsQuic.Schannel. It affects 6 products.
| Package | Affected | Fixed in |
|---|---|---|
Microsoft.Native.Quic.MsQuic.OpenSSL NuGet | All versions | 2.4.19 |
Microsoft.Native.Quic.MsQuic.OpenSSL NuGet | All versions | 2.4.19 |
Microsoft.Native.Quic.MsQuic.OpenSSL NuGet | From 2.5.3 | 2.5.10 |
Microsoft.Native.Quic.MsQuic.OpenSSL NuGet | From 2.5.3 | 2.5.10 |
Microsoft.Native.Quic.MsQuic.Schannel NuGet | All versions | 2.4.19 |
Microsoft.Native.Quic.MsQuic.Schannel NuGet | All versions | 2.4.19 |
2 more packages
Microsoft.Native.Quic.MsQuic.Schannel NuGet | From 2.5.3 | 2.5.10 |
Microsoft.Native.Quic.MsQuic.Schannel NuGet | From 2.5.3 | 2.5.10 |
Products include Microsoft Windows 11 23h2, Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, Microsoft Windows 11 26h1, Microsoft Windows Server 2022, Microsoft Windows Server 2025.
How do I fix CVE-2026-62815?
Upgrade Microsoft.Native.Quic.MsQuic.OpenSSL to a fixed version for your release line: 2.4.19 or 2.5.10.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-62815 being exploited?
There is no known exploitation of CVE-2026-62815 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Windows 11 23h2
- CVE-2026-81963 Microsoft Windows Link Following
- CVE-2026-100219 Microsoft QUIC Remote Code Execution Vulnerability
- CVE-2026-96909 Windows BitLocker Remote Code Execution Vulnerability
- CVE-2026-45657 Windows Kernel Remote Code Execution Vulnerability
- CVE-2026-41096 Windows DNS Client Remote Code Execution Vulnerability
Sources
Also known as GHSA-92f5-vc22-8j33.