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CVE-2026-43939

Estado: AplazadaAlta (7.3)—

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.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

XSS stored (CWE-79) en foro sin sanitización: inyección de JavaScript en posts. Vector PR:L indica acceso autenticado; UI:R + navegador web → T1189. Impacto: ejecución JS en cliente (T1059.007) y potencial robo de sesiones (T1078).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

User TrainingRestrict Web-Based ContentApplication Developer GuidanceActive Directory ConfigurationUser Account ManagementPrivileged Account Management

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Yetanotherforum — Yaf.netAI

CWE

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-43939",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-43939",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-05-13T14:32:49.648146Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.3,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.2,
        "exploitabilityScore": 2.1
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "YAFNET",
          "product": "YAFNET",
          "versions": [
            {
              "status": "affected",
              "version": ">= 4.0.0-beta.1, < 4.0.5"
            },
            {
              "status": "affected",
              "version": "< 3.2.12"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-05-12T15:16:15.647",
  "references": [
    {
      "url": "https://github.com/YAFNET/YAFNET/security/advisories/GHSA-8rq5-wwpp-fmj2",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/YAFNET/YAFNET/security/advisories/GHSA-8rq5-wwpp-fmj2",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        },
        {
          "lang": "en",
          "value": "CWE-80"
        },
        {
          "lang": "en",
          "value": "CWE-116"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "lastModified": "2026-06-17T10:50:05.800",
  "sourceIdentifier": "security-advisories@github.com"
}