CVE-2021-26085

Estado: AnalizadaMedia (5.3)⚠ Explotación activa

Affected versions of Atlassian Confluence Server allow remote attackers to view restricted resources via a Pre-Authorization Arbitrary File Read vulnerability in the /s/ endpoint. The affected versions are before version 7.4.10, and from version 7.5.0 before 7.12.3.

CVSS

Versión: 3.1
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Puntuación base: 5.3

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 100%
Percentil entre todas las CVEs puntuadas: 100
Fecha de la puntuación: 29/9/2026

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).

CISA KEV — explotada activamente

Añadida al catálogo: 28/3/2022
Plazo de remediación: 18/4/2022
Uso conocido en ransomware: Known

🎯 Técnicas ATT&CK

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

ExplotaciónT1190 Exploit Public-Facing Applicationinitial access95 %
Impacto principalT1005 Data from Local Systemcollection90 %

Vulnerabilidad de lectura arbitraria de archivos en endpoint /s/ de Confluence expuesto en red sin autenticación (AV:N, PR:N). Permite acceso a recursos restringidos, clasificado como acceso a datos locales (T1005).

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

Vulnerability Scanning Privileged Account Management Network Segmentation Limit Access to Resource Over Network Filter Network Traffic Application Isolation and Sandboxing

Tecnologías afectadas (2)

Atlassian — Confluence Data Center Atlassian — Confluence Server

CWE

CWE-425
CWE-425

Referencias

JSON original (NVD)

Mostrar

{
  "id": "CVE-2021-26085",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2021-26085",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "active"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2025-02-07T12:29:39.323995Z"
        }
      }
    ],
    "cvssMetricV2": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "version": "2.0",
          "baseScore": 5,
          "accessVector": "NETWORK",
          "vectorString": "AV:N/AC:L/Au:N/C:P/I:N/A:N",
          "authentication": "NONE",
          "integrityImpact": "NONE",
          "accessComplexity": "LOW",
          "availabilityImpact": "NONE",
          "confidentialityImpact": "PARTIAL"
        },
        "acInsufInfo": false,
        "impactScore": 2.9,
        "baseSeverity": "MEDIUM",
        "obtainAllPrivilege": false,
        "exploitabilityScore": 10,
        "obtainUserPrivilege": false,
        "obtainOtherPrivilege": false,
        "userInteractionRequired": false
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 3.9
      },
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "LOW"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "security@atlassian.com",
      "affectedData": [
        {
          "vendor": "Atlassian",
          "product": "Confluence Server",
          "versions": [
            {
              "status": "affected",
              "version": "unspecified",
              "lessThan": "7.4.10",
              "versionType": "custom"
            },
            {
              "status": "affected",
              "version": "7.5.0",
              "lessThan": "unspecified",
              "versionType": "custom"
            },
            {
              "status": "affected",
              "version": "unspecified",
              "lessThan": "7.12.3",
              "versionType": "custom"
            }
          ]
        },
        {
          "vendor": "Atlassian",
          "product": "Confluence Data Center",
          "versions": [
            {
              "status": "affected",
              "version": "unspecified",
              "lessThan": "7.4.10",
              "versionType": "custom"
            },
            {
              "status": "affected",
              "version": "7.5.0",
              "lessThan": "unspecified",
              "versionType": "custom"
            },
            {
              "status": "affected",
              "version": "unspecified",
              "lessThan": "7.12.3",
              "versionType": "custom"
            }
          ]
        }
      ]
    }
  ],
  "published": "2021-08-03T00:15:08.557",
  "references": [
    {
      "url": "http://packetstormsecurity.com/files/164401/Atlassian-Confluence-Server-7.5.1-Arbitrary-File-Read.html",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "security@atlassian.com"
    },
    {
      "url": "https://jira.atlassian.com/browse/CONFSERVER-67893",
      "tags": [
        "Issue Tracking",
        "Vendor Advisory"
      ],
      "source": "security@atlassian.com"
    },
    {
      "url": "http://packetstormsecurity.com/files/164401/Atlassian-Confluence-Server-7.5.1-Arbitrary-File-Read.html",
      "tags": [
        "Exploit",
        "Third Party Advisory",
        "VDB Entry"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://jira.atlassian.com/browse/CONFSERVER-67893",
      "tags": [
        "Issue Tracking",
        "Vendor Advisory"
      ],
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    },
    {
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26085",
      "tags": [
        "US Government Resource"
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-425"
        }
      ]
    },
    {
      "type": "Secondary",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "description": [
        {
          "lang": "en",
          "value": "CWE-425"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Affected versions of Atlassian Confluence Server allow remote attackers to view restricted resources via a Pre-Authorization Arbitrary File Read vulnerability in the /s/ endpoint. The affected versions are before version 7.4.10, and from version 7.5.0 before 7.12.3."
    },
    {
      "lang": "es",
      "value": "Las versiones afectadas de Atlassian Confluence Server permiten a los atacantes remotos visualizar recursos restringidos por medio de una vulnerabilidad de lectura arbitraria de archivos de autorización previa en el endpoint /s/.&#xa0;Las versiones afectadas son anteriores a la versión 7.4.10 y desde la versión 7.5.0 anteriores a 7.12.3"
    }
  ],
  "lastModified": "2026-06-17T03:42:49.933",
  "cisaActionDue": "2022-04-18",
  "cisaExploitAdd": "2022-03-28",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "83557716-7A48-48D5-85A9-4A29DBF4F511",
              "versionEndExcluding": "7.4.10"
            },
            {
              "criteria": "cpe:2.3:a:atlassian:confluence_data_center:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "6A310D77-1FFF-4FFE-AD50-75DFF973EB3F",
              "versionEndExcluding": "7.12.3",
              "versionStartIncluding": "7.5.0"
            },
            {
              "criteria": "cpe:2.3:a:atlassian:confluence_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "4BA04112-3B97-491B-93E6-80C444274430",
              "versionEndExcluding": "7.4.10"
            },
            {
              "criteria": "cpe:2.3:a:atlassian:confluence_server:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "B1148DF0-42C0-435F-A6EB-EFA93E10E8D7",
              "versionEndExcluding": "7.12.3",
              "versionStartIncluding": "7.5.0"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security@atlassian.com",
  "cisaRequiredAction": "Apply updates per vendor instructions.",
  "cisaVulnerabilityName": "Atlassian Confluence Server Pre-Authorization Arbitrary File Read Vulnerability"
}