Listen to this Post
CVE-2026-62815 is a critical use-after-free (CWE-416) vulnerability in Microsoft’s QUIC implementation. Microsoft QUIC is a foundational transport layer protocol designed for high-performance, encrypted communication across networks, often embedded in public-facing services like web servers and edge gateways. The vulnerability arises from improper memory management when the QUIC component handles specially crafted network packets.
Specifically, the software reuses or references memory after it has been freed. New network path creations and removals triggered by incoming packets can lead to a pointer invalidation. At some point after the memory is freed, it may be allocated again and saved in another pointer, while the original pointer still references a location within the new allocation. Any operations using the original pointer are no longer valid, as the memory now belongs to the code that operates on the new pointer. An attacker can leverage this memory corruption to manipulate how the system processes data, potentially allowing them to run unauthorized code.
An unauthenticated attacker can exploit this vulnerability remotely by sending a specially crafted packet to an affected service over the network. Successful exploitation could allow the attacker to execute arbitrary code on the target system with high impact on confidentiality, integrity, and availability. No authentication or user interaction is required, making the attack vector highly dangerous. The vulnerability carries a CVSS 3.1 base score of 9.8 (Critical), reflecting its network accessibility, low attack complexity, and the lack of required privileges or user interaction.
DailyCVE Form:
Platform: Windows 11, Windows Server
Version: 23H2-26H1, Server 2022/2025
Vulnerability: Use-After-Free (CWE-416)
Severity: Critical (CVSS 9.8)
Date: August 11, 2026
Prediction: Expected Patch Date: August 2026
What Undercode Say:
The following commands can be used to check for the presence of the vulnerable QUIC component and to identify potentially affected systems.
Check for QUIC support in Windows:
Get-NetTransportFilter | Where-Object { $_.SettingName -eq "QUIC" }
Identify systems with Microsoft QUIC enabled using asset discovery tools:
Get-WindowsOptionalFeature -Online -FeatureName QUIC
Check the current build version to verify if it matches the affected versions:
Exploit: (Educational Purposes!)
An attacker would craft a malicious network packet designed to trigger the use-after-free condition in the Microsoft QUIC component. By sending this packet to a target system running a vulnerable version of Windows with QUIC enabled, the attacker can cause memory corruption. This corruption can then be leveraged to execute arbitrary code on the target system. The attack requires no user interaction and can be performed remotely over the network.
A conceptual representation of the attack vector:
Attacker -> [Crafted Packet] -> Target System (Port: QUIC) -> Memory Corruption -> Code Execution
Protection:
- Apply Security Update: Install the Microsoft security update for CVE-2026-62815 released in the August 2026 security update cycle. Affected versions are addressed in specific builds:
Windows 11 23H2: 10.0.22631.7517
Windows 11 24H2: 10.0.26100.9106 / 10.0.26100.9168
Windows 11 25H2: 10.0.26200.9168
Windows 11 26H1: 10.0.28000.2704
Windows Server 2022: 10.0.20348.5440 / 10.0.20348.5499
Windows Server 2025: 10.0.26100.33222 / 10.0.26100.33296
2. Prioritize Patching: Prioritize internet-reachable and network-exposed systems.
- Disable QUIC (if feasible): If immediate patching is not possible, reduce exposure by disabling affected QUIC-enabled functionality where operationally feasible.
- Restrict Network Access: Limit network reachability to vulnerable services and restrict access to trusted networks or administrative boundaries until updates can be applied.
Impact:
Successful exploitation of CVE-2026-62815 allows an unauthenticated remote attacker to execute arbitrary code on the target system. This can lead to a full system compromise, allowing the attacker to:
Compromise data confidentiality
Alter system integrity
Interrupt services and availability
Gain control of code execution
Potentially use the compromised system as a pivot point for further attacks within the network.
🎯Let’s Practice Exploiting & Learn Patching For Free:
🎓 Live Courses & Certifications:
Join Undercode Academy for Verified Certifications
🚀 Request a Custom Project:
Secure, high-velocity infrastructure and disruptive technological engineering. Contact our engineering team for high-tier development and proprietary systems:
[email protected]
💎 Smart Architecture | 🛡️ Secure by Design | ⭐ Trusted by Thousands
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
