Potential DoS Vulnerability through Multiple KeyShareEntry with Same Group in TLS 1.3 ClientHello

{
  "id": "5d587c620438dcd993b07d7b8869fab2d892de676b2add6a084417527bbc34db",
  "url": "https://osv.dev/vulnerability/CVE-2025-11936",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Potential DoS Vulnerability through Multiple KeyShareEntry with Same Group in TLS 1.3 ClientHello",
    "summary": "Improper input validation in the TLS 1.3 KeyShareEntry parsing in wolfSSL v5.8.2 on multiple platforms allows a remote unauthenticated attacker to cause a denial-of-service by sending a crafted ClientHello message containing duplicate KeyShareEntry values for the same supported group, leading to excessive CPU and memory consumption during ClientHello processing.",
    "evidence": "osv:CVE-2025-11936",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-11936",
      "aliases": [
        "CVE-2025-11936"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/wolfssl/wolfssl",
              "type": "GIT",
              "events": [
                {
                  "introduced": "decea12e223869c8f8f3ab5a53dc90b69f436eb2"
                },
                {
                  "fixed": "59f4fa568615396fbf381b073b220d1e8d61e4c2"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "5.8.2"
                      },
                      {
                        "fixed": "5.8.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v5.8.2-stable"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-11936.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:33.009111451Z",
      "provider": "osv",
      "references": [
        "https://www.wolfssl.com/download/",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/11xxx/CVE-2025-11936.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-11936",
        "https://github.com/wolfSSL/wolfssl/pull/9117",
        "https://github.com/wolfSSL/wolfssl"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-20"
        ],
        "cna_assigner": "wolfSSL",
        "unresolved_ranges": [
          {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "3.12.0"
                  },
                  {
                    "fixed": "5.8.4"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StandardRange"
              }
            ]
          }
        ],
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/11xxx/CVE-2025-11936.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-11936",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 500183,
  "published_at": "2025-11-21T22:24:27.443+00:00"
}