Vulnerability · Published Aug 11, 2026 · Assigned by microsoft
CVE-2026-62815Microsoft QUIC Remote Code Execution Vulnerability
Critical 9.8
In plain English
A critical-severity use-after-free in Windows 11 version 23H2 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 62% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)1.0%top 37.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| NuGet | microsoft.native.quic.msquic.openssl | 2.5.10 | GHSA-92f5-vc22-8j33 |
| NuGet | microsoft.native.quic.msquic.openssl | 2.4.19 | GHSA-92f5-vc22-8j33 |
| NuGet | microsoft.native.quic.msquic.schannel | 2.5.10 | GHSA-92f5-vc22-8j33 |
| NuGet | microsoft.native.quic.msquic.schannel | 2.4.19 | GHSA-92f5-vc22-8j33 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Windows 11 version 23H2 | 10.0.22631.0 – before 10.0.22631.7517 |
| Microsoft | Windows 11 Version 23H2 | 10.0.22631.0 – before 10.0.22631.7517 |
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 – before 10.0.26100.9168 |
| Microsoft | Windows 11 Version 25H2 | 10.0.26200.0 – before 10.0.26200.9168 |
| Microsoft | Windows 11 version 26H1 | 10.0.28000.0 – before 10.0.28000.2704 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 – before 10.0.20348.5499 |
| Microsoft | Windows Server 2025 | 10.0.26100.0 – before 10.0.26100.33296 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 – before 10.0.26100.33296 |
Weakness: CWE-416 · Vector: 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
References
- Microsoft QUIC Remote Code Execution Vulnerability vendor-advisory, patch