{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "4.0.0-beta.1"
              },
              {
                "fixed": "4.0.5"
              },
              {
                "introduced": "0"
              },
              {
                "fixed": "3.2.12"
              }
            ],
            "source": "AFFECTED_FIELD"
          },
          "events": [
            {
              "introduced": "c2932f06fe41f11e723879f8febf3e96b91d5750"
            },
            {
              "fixed": "3cb0ee7fbc01f8d3e84eaddf55350aced2dd4bfc"
            },
            {
              "introduced": "0"
            },
            {
              "fixed": "28579da80af507294dbdf9ae5b44ad9c185d0720"
            }
          ],
          "repo": "https://github.com/yafnet/yafnet",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-8rq5-wwpp-fmj2"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-116",
      "CWE-79",
      "CWE-80"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43939.json"
  },
  "details": "YetAnotherForum.NET (YAF.NET) is a C# ASP.NET forum. Prior to 4.0.5 and 3.2.12, the thread posting and reply feature accepts user-supplied content via a a post or reply that is stored server-side and later rendered back into the thread page without adequate HTML sanitization or contextual output encoding.  This vulnerability is fixed in 4.0.5 and 3.2.12.",
  "id": "CVE-2026-43939",
  "modified": "2026-08-12T03:51:30.444601435Z",
  "published": "2026-05-12T13:56:39.586Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43939.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/YAFNET/YAFNET/security/advisories/GHSA-8rq5-wwpp-fmj2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43939"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "YAF.NET: Stored XSS in Forum Thread Posts/Replies Allowing Arbitrary JavaScript Execution for All Thread Viewers"
}