CVE-2026-62815: Microsoft QUIC Remote Code Execution Vulnerability

Published Aug 11, 2026
·
Updated

Summary Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.

Details

New network path creations and removals triggered by incoming packets can lead to a pointer invalidation.

Patches

- Guard path promotion e0f55b5

Impact

An unauthenticated attacker could exploit this vulnerability by sending a specially crafted packet to an affected service over the network. Successful exploitation could allow the attacker to execute code on the target system. No authentication or user interaction is required.

Other sources

Microsoft QUIC Remote Code Execution Vulnerability

— Microsoft

Affected Software

26 affected componentsFixes available
Microsoft Windows Server 2025<10.0.26100.33296, <10.0.26100.33222
10.0.26100.3329610.0.26100.33222
Microsoft Windows 11=26H1
10.0.28000.2704
Microsoft Windows 11=26H1
10.0.28000.2704
Microsoft Windows Server 2022<10.0.20348.5499, <10.0.20348.5440
10.0.20348.549910.0.20348.5440
Microsoft Windows 11=23H2
10.0.22631.7517
Microsoft Windows 11=23H2
10.0.22631.7517
Microsoft Windows Server 2025<10.0.26100.33296, <10.0.26100.33222
10.0.26100.3329610.0.26100.33222
Microsoft Windows Server 2022<10.0.20348.5499, <10.0.20348.5440
10.0.20348.549910.0.20348.5440
Microsoft Windows 11=24H2
10.0.26100.916810.0.26200.9106
Microsoft Windows 11=25H2
10.0.26200.916810.0.26200.9106
Microsoft Windows 11=24H2
10.0.26100.916810.0.26100.9106
Microsoft Windows 11=25H2
10.0.26200.916810.0.26200.9106
Microsoft Windows 11 23h2<10.0.22631.7517
Microsoft Windows 11 23h2<10.0.22631.7517
Microsoft Windows 11 24h2<10.0.26100.9106
Microsoft Windows 11 24h2<10.0.26100.9106
Microsoft Windows 11 25h2<10.0.26200.9106
Microsoft Windows 11 25h2<10.0.26200.9106
Microsoft Windows 11 26h1<10.0.28000.2704
Microsoft Windows 11 26h1<10.0.28000.2704
Microsoft Windows Server 2022<10.0.20348.5440
Microsoft Windows Server 2025<10.0.26100.33222
nuget/Microsoft.Native.Quic.MsQuic.Schannel<2.4.19
2.4.19
nuget/Microsoft.Native.Quic.MsQuic.OpenSSL<2.4.19
2.4.19
nuget/Microsoft.Native.Quic.MsQuic.Schannel>=2.5.3<2.5.10
2.5.10
nuget/Microsoft.Native.Quic.MsQuic.OpenSSL>=2.5.3<2.5.10
2.5.10

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.33296Fixed in 10.0.26100.33222Patch KB5120228
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.28000.2704Patch KB5121000
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.20348.5499Fixed in 10.0.20348.5440Patch KB5120229
  4. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.22631.7517Patch KB5120240
  5. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26200.9168Fixed in 10.0.26200.9106Patch KB5120994
  6. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.9168Fixed in 10.0.26200.9106Patch KB5120994
  7. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 10.0.26100.9168Fixed in 10.0.26100.9106Patch KB5120994
  8. Upgrade

    Upgrade nuget/Microsoft.Native.Quic.MsQuic.Schannel to a version that resolves this vulnerability.

    Fixed in 2.4.19
  9. Upgrade

    Upgrade nuget/Microsoft.Native.Quic.MsQuic.OpenSSL to a version that resolves this vulnerability.

    Fixed in 2.4.19
  10. Upgrade

    Upgrade nuget/Microsoft.Native.Quic.MsQuic.Schannel to a version that resolves this vulnerability.

    Fixed in 2.5.10
  11. Upgrade

    Upgrade nuget/Microsoft.Native.Quic.MsQuic.OpenSSL to a version that resolves this vulnerability.

    Fixed in 2.5.10

Event History

Aug 11, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
CVE Published
via MITRE·05:04 PM
Data Sourced
via MITRE·05:04 PM
DescriptionSeverity
Data Sourced
via NVD·05:18 PM
RemedyDescriptionSeverityWeaknessAffected Software
Sep 8, 2026
Advisory Published
via GitHub·08:27 PM
Data Sourced
via GitHub·08:27 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2026-62815?

CVE-2026-62815 has a critical severity rating of 9.8.

2

How can I mitigate CVE-2026-62815?

To mitigate CVE-2026-62815, ensure that your Microsoft Windows systems are updated with the latest security patches.

3

What systems are affected by CVE-2026-62815?

CVE-2026-62815 affects Microsoft Windows 11, Windows Server 2025, and Windows Server 2022.

4

What type of vulnerability is CVE-2026-62815?

CVE-2026-62815 is classified as a Use After Free vulnerability which can lead to remote code execution.

5

What impact does CVE-2026-62815 have on affected systems?

CVE-2026-62815 allows unauthorized attackers to execute code remotely on affected systems over a network.

Company

Resources

Contact

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