# CVE-2023-35838: WireGuard: The WireGuard client 0.5.3 on Windows insecurely configures the operating system and firewall such that…

CVE-2023-35838 is fixed in WireGuard on 1 platform by WireGuard 0.6.1 (version 0.6.1), released April 10, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2023-35838
- Priority: Routine
- CVSS: 5.7
- EPSS: 0.0069
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 9, 2023
- Vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2023-35838

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Windows apps | WireGuard | 0.6.1 | [WireGuard 0.6.1](https://patchblox.com/security/data/fix/windows-app/wireguard.wireguard-0.6.1.md) | Apr 10, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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