CVE-2026-40165

{
  "id": "CVE-2026-40165",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-40165",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-05-21T14:13:10.961177Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 8.7,
          "attackVector": "NETWORK",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "HIGH",
          "availabilityImpact": "NONE",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.8,
        "exploitabilityScore": 2.2
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "goauthentik",
          "product": "authentik",
          "versions": [
            {
              "status": "affected",
              "version": "< 2025.12.5"
            },
            {
              "status": "affected",
              "version": ">= 2026.2.0-rc1, < 2026.2.3"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-05-21T00:16:28.290",
  "references": [
    {
      "url": "https://github.com/goauthentik/authentik/commit/47dec5c6b7fb4a62bfad2ae8bddf002bde7ba774",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/goauthentik/authentik/releases/tag/version%2F2025.12.5",
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/goauthentik/authentik/security/advisories/GHSA-9wj8-xv4r-qwrp",
      "source": "security-advisories@github.com"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-91"
        },
        {
          "lang": "en",
          "value": "CWE-287"
        },
        {
          "lang": "en",
          "value": "CWE-436"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "authentik is an open-source identity provider. Versions 2025.12.4 and prior, and versions 2026.2.0-rc1 through 2026.2.2 were vulnerable to Authentication Bypass through SAML NameID XML Comment Injection. Due to how authentik extracted the NameID value from a SAML assertion, it was possible for an attacker to trick authentik into only seeing a part of the NameID value, potentially allowing an attacker to gain access to other accounts. This issue could be exploited on an authentik instance with a SAML Source, where the attacker had an account on the SAML Source and the ability to modify their NameID value (commonly username or E-mail), and XML Signing was enabled. The attacker could modify the SAML assertion given to authentik by injecting a comment within the NameID value, which effectively truncated the NameID value to the snippet before the comment, and gave the attacker access to any user account. This issue has been fixed in versions 2025.12.5 and 2026.2.3."
    },
    {
      "lang": "es",
      "value": "authentik es un proveedor de identidad de código abierto. Las versiones 2025.12.4 y anteriores, y las versiones 2026.2.0-rc1 hasta la 2026.2.2 eran vulnerables a la omisión de autenticación a través de la inyección de comentarios XML en el NameID de SAML. Debido a cómo authentik extraía el valor NameID de una aserción SAML, era posible para un atacante engañar a authentik para que solo viera una parte del valor NameID, lo que potencialmente permitía a un atacante obtener acceso a otras cuentas. Este problema podía ser explotado en una instancia de authentik con una fuente SAML, donde el atacante tenía una cuenta en la fuente SAML y la capacidad de modificar su valor NameID (comúnmente nombre de usuario o correo electrónico), y la firma XML estaba habilitada. El atacante podía modificar la aserción SAML proporcionada a authentik inyectando un comentario dentro del valor NameID, lo que efectivamente truncaba el valor NameID al fragmento anterior al comentario, y le daba al atacante acceso a cualquier cuenta de usuario. Este problema ha sido solucionado en las versiones 2025.12.5 y 2026.2.3."
    }
  ],
  "lastModified": "2026-07-23T15:10:00.137",
  "sourceIdentifier": "security-advisories@github.com"
}