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CVE-2026-40872

Full vulnerability record from the local CVENow database.

Description

mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the admin dashboard's Autodiscover logs render the EMailAddress value (logged as the "user" field) without HTML escaping. By submitting an unauthenticated Autodiscover request with a crafted EMailAddress containing HTML/JS, the payload is stored in Redis and executed when an admin views the Autodiscover logs. Version 2026-03b fixes the vulnerability.

Severity
CRITICAL
CVSS score
9.3 (v4.0)
Vulnerability status
Deferred
Source identifier
Published
2026-04-21 20:17:00.673000
Last modified
2026-10-26 21:10:00.170000
View original CVE JSON
{
  "id": "CVE-2026-40872",
  "sourceIdentifier": "[email protected]",
  "published": "2026-04-21T20:17:00.673",
  "lastModified": "2026-10-26T21:10:00.170",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "mailcow: dockerized is an open source groupware/email suite based on docker. In versions prior to 2026-03b, the admin dashboard's Autodiscover logs render the EMailAddress value (logged as the \"user\" field) without HTML escaping. By submitting an unauthenticated Autodiscover request with a crafted EMailAddress containing HTML/JS, the payload is stored in Redis and executed when an admin views the Autodiscover logs. Version 2026-03b fixes the vulnerability."
    },
    {
      "lang": "es",
      "value": "mailcow: dockerized es una suite de groupware/correo electrónico de código abierto basada en Docker. En versiones anteriores a 2026-03b, los registros de Autodiscover del panel de administración renderizan el valor EMailAddress (registrado como el campo ’user’) sin escape HTML. Al enviar una solicitud de Autodiscover no autenticada con un EMailAddress manipulado que contiene HTML/JS, la carga útil se almacena en Redis y se ejecuta cuando un administrador ve los registros de Autodiscover. La versión 2026-03b corrige la vulnerabilidad."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "mailcow",
          "product": "mailcow-dockerized",
          "versions": [
            {
              "version": "< 2026-03b",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "baseScore": 9.3,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "PASSIVE",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "HIGH",
          "vulnAvailabilityImpact": "HIGH",
          "subConfidentialityImpact": "HIGH",
          "subIntegrityImpact": "HIGH",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-04-22T13:36:53.186880Z",
          "id": "CVE-2026-40872",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        },
        {
          "lang": "en",
          "value": "CWE-80"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-f9xf-vc72-rcgm",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/mailcow/mailcow-dockerized/security/advisories/GHSA-f9xf-vc72-rcgm",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}