Security advisory

{
  "id": "c65f9192f5d8c1cd43afa9861fcc684830ad9572b71add330acb7b7765ce8303",
  "url": "https://osv.dev/vulnerability/CVE-2023-35838",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2023-35838",
    "summary": "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.",
    "evidence": "osv:CVE-2023-35838",
    "products": [],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2023-35838",
      "aliases": [
        "CVE-2023-35838",
        "PYSEC-2023-321"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/wireguard/wireguard-windows",
              "type": "GIT",
              "events": [
                {
                  "introduced": "28e903804aa1302b791c24093dd7f42f0c7d0952"
                },
                {
                  "last_affected": "28e903804aa1302b791c24093dd7f42f0c7d0952"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:wireguard:wireguard:0.5.3:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.5.3"
                      },
                      {
                        "last_affected": "0.5.3"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "0.5.3",
            "v0.5.3"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-35838.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:50.705328100Z",
      "provider": "osv",
      "references": [
        "https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2023-0015",
        "https://tunnelcrack.mathyvanhoef.com/details.html",
        "https://wireguard.com",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/35xxx/CVE-2023-35838.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-35838"
      ],
      "provider_metadata": {
        "cna_assigner": "mitre",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/35xxx/CVE-2023-35838.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-35838",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 519435,
  "published_at": "2023-08-09T00:00:00+00:00"
}