WireGuard, such as WireGuard 0.5.3 on Windows, does not fully account for the possibility that an adversary might be able to set a victim's system time to a future value, e.g., because unauthenticated NTP is used. This can lead to an outcome in which one static private key becomes permanently useless.

The WireGuard client 0.5.3 on Windows insecurely configures the operating system and firewall such that traffic to a local network that uses non-RFC1918 IP addresses is blocked. This allows an adversary to trick the victim into blocking IP traffic to selected IP addresses and services even while the VPN is enabled. NOTE: the tunnelcrack.mathyvanhoef.com website uses this CVE ID to refer more generally to "LocalNet attack resulting in the blocking of traffic" rather than to only WireGuard.