CVE-2026-62757

Windows Schannel is part of Windows that helps protect network connections and checks digital signatures. This flaw lets an attacker trick it into “trusting” bad signatures, similar to getting a bouncer to wave through the wrong-looking ID. The main risk is that attackers can affect what your system believes is authentic, which can lead to integrity problems.

This matters if you run Windows 10, Windows 11, or any of these Windows Server versions (2012/2012 R2, 2016, 2019, 2022, 2025) on devices that communicate over a network with untrusted users or systems. Because the weakness involves network traffic and Windows Schannel doing cryptographic verification, exposure is tied to whether your systems use Schannel for network security (for example, TLS/secure communications). Based on the available findings, it is only a meaningful risk when an attacker can reach the vulnerable service path over the network and provide maliciously crafted input; default reachability is not yet known.

This is RED because the vulnerability is a security check bypass in Windows Schannel that can let attackers undermine authenticity verification over the network. Even though confirmed public exploitation is not clearly reported in the findings, the patch availability for many supported Windows versions and the “actor: Lazarus group” signal from the bulletin makes it urgent to remove the risk by updating promptly.