CVE-2026-15076

Full vulnerability record from the local CVENow database.

Description

In versions up to and including 4.5.29 (4.x branch) and 5.1.4 (5.x branch), the WebClientSession component of Eclipse Vert.x Web Client does not validate that the Domain attribute of a Set-Cookie response header matches the originating server's domain, in violation of RFC 6265 section 5.3. An attacker who controls any server that the victim application contacts can inject a cookie scoped to an arbitrary third-party domain; because the session store performs no cross-domain ownership check, it stores and later transmits that cookie to the targeted domain. When the victim application subsequently sends a request to the targeted domain using the same WebClientSession, it presents the attacker-injected cookie, causing the receiving service to process the request under the attacker's account. Sensitive data included in the victim application's requests, such as payment amounts, card details, or other API payloads, may then be accessible to the attacker through their own account on that service.

Severity

HIGH

CVSS score

8.2 (v4.0)

Vulnerability status

Analyzed

Source identifier

[email protected]

Published

2026-07-14 09:16:40.313000

Last modified

2026-10-24 22:10:00.210000

View original CVE JSON

{
  "id": "CVE-2026-15076",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-14T09:16:40.313",
  "lastModified": "2026-10-24T22:10:00.210",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In versions up to and including 4.5.29 (4.x branch) and 5.1.4 (5.x branch), the WebClientSession component of Eclipse Vert.x Web Client does not validate that the Domain attribute of a Set-Cookie response header matches the originating server's domain, in violation of RFC 6265 section 5.3.\nAn attacker who controls any server that the victim application contacts can inject a cookie scoped to an arbitrary third-party domain; because the session store performs no cross-domain ownership check, it stores and later transmits that cookie to the targeted domain.\n\n\n\n\nWhen the victim application subsequently sends a request to the targeted domain using the same WebClientSession, it presents the attacker-injected cookie, causing the receiving service to process the request under the attacker's account. Sensitive data included in the victim application's requests, such as payment amounts, card details, or other API payloads, may then be accessible to the attacker through their own account on that service."
    },
    {
      "lang": "es",
      "value": "En versiones hasta la 4.5.29 (inclusive) (rama 4.x) y la 5.1.4 (rama 5.x), el componente WebClientSession de Eclipse Vert.x Web Client no valida que el atributo Domain de una cabecera de respuesta Set-Cookie coincida con el dominio del servidor de origen, en violación de la sección 5.3 de RFC 6265.\nUn atacante que controla cualquier servidor con el que la aplicación víctima contacta puede inyectar una cookie con ámbito a un dominio de terceros arbitrario; debido a que el almacén de sesiones no realiza ninguna comprobación de propiedad entre dominios, almacena y posteriormente transmite esa cookie al dominio objetivo.\n\nCuando la aplicación víctima posteriormente envía una solicitud al dominio objetivo utilizando la misma WebClientSession, presenta la cookie inyectada por el atacante, haciendo que el servicio receptor procese la solicitud bajo la cuenta del atacante. Datos sensibles incluidos en las solicitudes de la aplicación víctima, como importes de pago, detalles de tarjetas u otras cargas útiles de API, pueden entonces ser accesibles para el atacante a través de su propia cuenta en ese servicio."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "Eclipse Foundation",
          "product": "Eclipse Vert.x",
          "defaultStatus": "unaffected",
          "repo": "https://github.com/vert-x3/vertx-web",
          "versions": [
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              "version": "4.0.0",
              "lessThanOrEqual": "4.5.29",
              "versionType": "semver",
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            }
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  "metrics": {
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        "type": "Secondary",
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          "modifiedAttackComplexity": "NOT_DEFINED",
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          "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"
        }
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    ],
    "cvssMetricV31": [
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          "scope": "UNCHANGED",
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          "availabilityImpact": "NONE"
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      }
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    "ssvcV203": [
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          "id": "CVE-2026-15076",
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            },
            {
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            },
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          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-346"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
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          "negate": false,
          "cpeMatch": [
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  "references": [
    {
      "url": "https://gitlab.eclipse.org/security/cve-assignment/-/work_items/162",
      "source": "[email protected]",
      "tags": [
        "Issue Tracking"
      ]
    }
  ]
}