CVE-2026-62815
Microsoft QUIC Remote Code Execution Vulnerability
Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Microsoft QUIC Remote Code Execution Vulnerability
Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
- Record
CVE-2026-62815- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - Weakness
- CWE-416
- Updated
- 2026-11-02
EUVDEUVD-2026-56392
Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
- Record
EUVD-2026-56392- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-2q33-cf8w-7q23
Duplicate Advisory: Microsoft QUIC Remote Code Execution Vulnerability
Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-92f5-vc22-8j33. This link is maintained to preserve external references.
Original Description
Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
- Record
GHSA-2q33-cf8w-7q23- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
GitHub AdvisoriesGHSA-92f5-vc22-8j33
Microsoft QUIC: Remote Code Execution Vulnerability
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.
- Record
GHSA-92f5-vc22-8j33- CVSS 4.0
- 10.0 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
NVD
Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
- Record
CVE-2026-62815- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
OSVGHSA-2q33-cf8w-7q23
Duplicate Advisory: Microsoft QUIC Remote Code Execution Vulnerability
Duplicate Advisory
This advisory has been withdrawn because it is a duplicate of GHSA-92f5-vc22-8j33. This link is maintained to preserve external references.
Original Description
Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
- Record
GHSA-2q33-cf8w-7q23- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
OSVGHSA-92f5-vc22-8j33
Microsoft QUIC: Remote Code Execution Vulnerability
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.
- Record
GHSA-92f5-vc22-8j33- CVSS 4.0
- 10.0 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-416
- Updated
- 2026-11-02
Affected products
- microsoft windows 11 version 23h2
- microsoft windows 11 version 24h2
- microsoft windows 11 version 25h2
- microsoft windows 11 version 26h1
- microsoft windows server 2022
- microsoft windows server 2025
- microsoft windows server 2025 (server core installation)
- microsoft windows 11 23h2
- microsoft windows 11 24h2
- microsoft windows 11 25h2
- microsoft windows 11 26h1
Affected packages
| Package | Affected | Fixed |
|---|---|---|
Microsoft.Native.Quic.MsQuic.OpenSSLNuGet |
2.5.3 up to 2.5.10 | 2.5.10 |
Microsoft.Native.Quic.MsQuic.SchannelNuGet |
2.5.3 up to 2.5.10 | 2.5.10 |
Microsoft.Native.Quic.MsQuic.OpenSSLNuGet |
before 2.4.19 | 2.4.19 |
Microsoft.Native.Quic.MsQuic.SchannelNuGet |
before 2.4.19 | 2.4.19 |
Microsoft.Native.Quic.MsQuic.OpenSSLNuGet |
before 2.4.19, plus listed versions 1.8.0 |
2.4.19 |
Microsoft.Native.Quic.MsQuic.SchannelNuGet |
before 2.4.19, plus listed versions 1.8.0 |
2.4.19 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-62815 is a critical vulnerability (CVSS 9.8) in Microsoft Windows 11 Version 23h2, published August 11, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.97%, the 62nd percentile. Fixed in Microsoft.Native.Quic.MsQuic.OpenSSL 2.5.10.
References
msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62815
nvd.nist.gov/vuln/detail/CVE-2026-62815
github.com/advisories/GHSA-2q33-cf8w-7q23
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