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CVE-2026-13163

Full vulnerability record from the local CVENow database.

Description

Open redirect vulnerability (CWE-601) in the _safe_redirect function of the click-tracking endpoint (/c/<token>/) in Mailerup <1.0.0 on all platforms allows remote unauthenticated attackers to redirect victims to arbitrary external sites and conduct phishing attacks via a crafted u query parameter, because the URL scheme is validated (blocking javascript: and data:) but the destination host is not restricted to an allowlist, and a signing.BadSignature exception is silently caught so a valid signed token is not required.

Severity
MEDIUM
CVSS score
5.3 (v4.0)
Vulnerability status
Deferred
Source identifier
4daa8cea-433a-44bd-9456-53b127fc289a
Published
2026-06-24 13:16:31.993000
Last modified
2026-10-24 13:10:00.147000
View original CVE JSON
{
  "id": "CVE-2026-13163",
  "sourceIdentifier": "4daa8cea-433a-44bd-9456-53b127fc289a",
  "published": "2026-06-24T13:16:31.993",
  "lastModified": "2026-10-24T13:10:00.147",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Open redirect vulnerability (CWE-601) in the _safe_redirect function of the click-tracking endpoint (/c/<token>/) in Mailerup <1.0.0 on all platforms allows remote unauthenticated attackers to redirect victims to arbitrary external sites and conduct phishing attacks via a crafted u query parameter, because the URL scheme is validated (blocking javascript: and data:) but the destination host is not restricted to an allowlist, and a signing.BadSignature exception is silently caught so a valid signed token is not required."
    },
    {
      "lang": "es",
      "value": "Vulnerabilidad de redirección abierta (CWE-601) en la función _safe_redirect del endpoint de seguimiento de clics (/c/<token>/) en Mailerup anterior a 1.0.0 en todas las plataformas permite a atacantes remotos no autenticados redirigir a las víctimas a sitios externos arbitrarios y realizar ataques de phishing a través de un parámetro de consulta u elaborado, porque el esquema de URL es validado (bloqueando javascript: y data:) pero el host de destino no está restringido a una lista de permitidos, y una excepción signing.BadSignature es capturada silenciosamente por lo que no se requiere un token firmado válido."
    }
  ],
  "affected": [
    {
      "source": "4daa8cea-433a-44bd-9456-53b127fc289a",
      "affectedData": [
        {
          "vendor": "Mailerup",
          "product": "Mailerup",
          "defaultStatus": "unaffected",
          "repo": "https://github.com/Maalfer/mailerup",
          "versions": [
            {
              "version": "0",
              "lessThan": "1.0.1",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "4daa8cea-433a-44bd-9456-53b127fc289a",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:N/SI:L/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": 5.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "PASSIVE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "LOW",
          "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": "2026-06-24T13:06:55.947222Z",
          "id": "CVE-2026-13163",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "4daa8cea-433a-44bd-9456-53b127fc289a",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-601"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/Maalfer/mailerup/commit/99eb6d4586134bf3f4422093fbf47d6794ef0ee5",
      "source": "4daa8cea-433a-44bd-9456-53b127fc289a"
    }
  ]
}