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CVE-2026-100635

Estado: AplazadaAlta (8.2)—

SiYuan before v3.8.4 contains an authentication bypass vulnerability in the publish service where session cookies are issued without Secure or SameSite attributes over plaintext HTTP connections. An on-path attacker can observe a valid publish-visitor-session-id cookie from a Basic Auth exchange and replay it to access authenticated publish endpoints without knowing the account password.

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.

Aplicación web expuesta (SiYuan) con bypass de autenticación por cookies inseguras (sin Secure/SameSite) en HTTP; atacante en ruta observa y reutiliza session-id válida para acceder sin credenciales.

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

Password PoliciesVulnerability ScanningUser TrainingRestrict File and Directory PermissionsPrivileged Account ManagementNetwork Segmentation

Tecnologías afectadas (1)

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

B3log — SiyuanAI

CWE

Referencias

JSON original (NVD)

Mostrar
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  "id": "CVE-2026-100635",
  "cveTags": [],
  "metrics": {
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        "ssvcData": {
          "id": "CVE-2026-100635",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
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          "version": "2.0.3",
          "timestamp": "2026-09-28T18:53:29.876873Z"
        }
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    "cvssMetricV31": [
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          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "integrityImpact": "NONE",
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    "cvssMetricV40": [
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          "version": "4.0",
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          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "valueDensity": "NOT_DEFINED",
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          "exploitMaturity": "NOT_DEFINED",
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          "subIntegrityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
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          "vulnAvailabilityImpact": "NONE",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
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          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
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  "affected": [
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      "affectedData": [
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          "vendor": "siyuan-note",
          "product": "siyuan",
          "versions": [
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              "version": "0",
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              "versionType": "semver"
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            {
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              "version": "3.8.4",
              "versionType": "semver"
            }
          ],
          "packageURL": "pkg:npm/siyuan-note/siyuan",
          "defaultStatus": "unaffected"
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  "published": "2026-09-26T14:16:45.007",
  "references": [
    {
      "url": "https://github.com/siyuan-note/siyuan/commit/79d47867b106467c951475a9193455b48d1f3682",
      "source": "disclosure@vulncheck.com"
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      "source": "disclosure@vulncheck.com"
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    },
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  "vulnStatus": "Deferred",
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      "description": [
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          "lang": "en",
          "value": "CWE-319"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "SiYuan before v3.8.4 contains an authentication bypass vulnerability in the publish service where session cookies are issued without Secure or SameSite attributes over plaintext HTTP connections. An on-path attacker can observe a valid publish-visitor-session-id cookie from a Basic Auth exchange and replay it to access authenticated publish endpoints without knowing the account password."
    }
  ],
  "lastModified": "2026-09-28T19:16:44.560",
  "sourceIdentifier": "disclosure@vulncheck.com"
}