CVE-2026-62898

Microsoft QUIC is a fast networking feature used for certain modern internet connections. This bug can accidentally reuse memory that should no longer be used, which can let an attacker over the network see confidential information. Think of it like handing out a scrap of paper that was “thrown away,” but someone else ends up reading the old message on it.

This matters if you build or run apps on affected .NET or Visual Studio versions that are using Microsoft QUIC for internet-facing network traffic. If Microsoft QUIC is not used, the risk may not apply, but the findings note the reachable-by-default status is unknown—so you should verify whether QUIC is enabled in your environment. Because the issue is network-accessible without authentication, it becomes a risk once an attacker can reach your QUIC-enabled endpoints.

This is RED because it’s an unauthenticated network information disclosure flaw in a commonly used platform component, and Microsoft has provided fixed versions for multiple supported branches. While a dated, clear public exploitation report isn’t provided here, the activity signal indicates real threat interest (including a named actor in patch-related reporting). Prioritize patching these components quickly, especially for any internet-facing QUIC usage.