CVE-2026-53431

Full vulnerability record from the local CVENow database.

Description

Authentication Bypass by Capture-replay vulnerability in malach-it Boruta allows an attacker who has obtained a previously valid JWT client assertion to authenticate as the issuing OAuth client after the assertion has expired. Boruta accepts JWT-based client authentication (client_secret_jwt and private_key_jwt token endpoint authentication methods) but never enforces that the assertion's exp claim is in the future. The pre-check helper Boruta.Oauth.Request.Base.check_expiration/1 in lib/boruta/oauth/request/base.ex only verifies that an exp claim is present (it pattern-matches on the existence of the key and returns success), and the Joken token configuration used for signature verification, Boruta.Oauth.Authorization.Client.Token.token_config/0 in lib/boruta/oauth/authorization/client.ex, returns an empty map, so Joken's default exp claim validator is not engaged either. Any attacker who obtains a validly-signed client assertion (for example through logs, reverse proxies, browser tooling, or other observability surfaces) can replay it indefinitely to authenticate as the client and obtain access tokens with that client's privileges. This issue affects boruta: from 2.3.0 before 2.3.7.

Severity

CRITICAL

CVSS score

9.1 (v4.0)

Vulnerability status

Deferred

Source identifier

6b3ad84c-e1a6-4bf7-a703-f496b71e49db

Published

2026-07-30 15:16:33.567000

Last modified

2026-10-23 22:10:00.160000

View original CVE JSON

{
  "id": "CVE-2026-53431",
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "published": "2026-07-30T15:16:33.567",
  "lastModified": "2026-10-23T22:10:00.160",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Authentication Bypass by Capture-replay vulnerability in malach-it Boruta allows an attacker who has obtained a previously valid JWT client assertion to authenticate as the issuing OAuth client after the assertion has expired.\n\nBoruta accepts JWT-based client authentication (client_secret_jwt and private_key_jwt token endpoint authentication methods) but never enforces that the assertion's exp claim is in the future. The pre-check helper Boruta.Oauth.Request.Base.check_expiration/1 in lib/boruta/oauth/request/base.ex only verifies that an exp claim is present (it pattern-matches on the existence of the key and returns success), and the Joken token configuration used for signature verification, Boruta.Oauth.Authorization.Client.Token.token_config/0 in lib/boruta/oauth/authorization/client.ex, returns an empty map, so Joken's default exp claim validator is not engaged either. Any attacker who obtains a validly-signed client assertion (for example through logs, reverse proxies, browser tooling, or other observability surfaces) can replay it indefinitely to authenticate as the client and obtain access tokens with that client's privileges.\n\nThis issue affects boruta: from 2.3.0 before 2.3.7."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de omisión de autenticación por captura-repetición en malach-it Boruta permite a un atacante que ha obtenido una aserción de cliente JWT previamente válida autenticarse como el cliente OAuth emisor después de que la aserción haya expirado.\n\nBoruta acepta la autenticación de cliente basada en JWT (métodos de autenticación de punto final de token client_secret_jwt y private_key_jwt) pero nunca impone que la declaración ’exp’ de la aserción esté en el futuro. La función auxiliar de pre-verificación Boruta.Oauth.Request.Base.check_expiration/1 en lib/boruta/oauth/request/base.ex solo verifica que una declaración ’exp’ esté presente (hace coincidir patrones con la existencia de la clave y devuelve éxito), y la configuración de token de Joken utilizada para la verificación de firma, Boruta.Oauth.Authorization.Client.Token.token_config/0 en lib/boruta/oauth/authorization/client.ex, devuelve un mapa vacío, por lo que el validador de declaración ’exp’ predeterminado de Joken tampoco se activa. Cualquier atacante que obtenga una aserción de cliente válidamente firmada (por ejemplo, a través de registros, proxies inversos, herramientas de navegador u otras superficies de observabilidad) puede reproducirla indefinidamente para autenticarse como el cliente y obtener tokens de acceso con los privilegios de ese cliente.\n\nEste problema afecta a boruta: desde 2.3.0 antes de 2.3.7."
    }
  ],
  "affected": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "affectedData": [
        {
          "vendor": "malach-it",
          "product": "boruta",
          "defaultStatus": "unaffected",
          "collectionURL": "https://repo.hex.pm",
          "packageName": "boruta",
          "cpes": [
            "cpe:2.3:a:malach-it:boruta_auth:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "'Elixir.Boruta.Oauth.Request.Base'",
            "'Elixir.Boruta.Oauth.Authorization.Client.Token'"
          ],
          "programFiles": [
            "lib/boruta/oauth/request/base.ex",
            "lib/boruta/oauth/authorization/client.ex"
          ],
          "programRoutines": [
            {
              "name": "'Elixir.Boruta.Oauth.Request.Base':fetch_client_authentication/1"
            },
            {
              "name": "'Elixir.Boruta.Oauth.Request.Base':check_expiration/1"
            },
            {
              "name": "'Elixir.Boruta.Oauth.Authorization.Client.Token':token_config/0"
            }
          ],
          "repo": "https://github.com/malach-it/boruta_auth",
          "packageURL": "pkg:hex/boruta",
          "versions": [
            {
              "version": "2.3.0",
              "lessThan": "2.3.7",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "malach-it",
          "product": "boruta",
          "defaultStatus": "unaffected",
          "collectionURL": "https://github.com",
          "packageName": "malach-it/boruta_auth",
          "cpes": [
            "cpe:2.3:a:malach-it:boruta_auth:*:*:*:*:*:*:*:*"
          ],
          "modules": [
            "'Elixir.Boruta.Oauth.Request.Base'",
            "'Elixir.Boruta.Oauth.Authorization.Client.Token'"
          ],
          "programFiles": [
            "lib/boruta/oauth/request/base.ex",
            "lib/boruta/oauth/authorization/client.ex"
          ],
          "programRoutines": [
            {
              "name": "'Elixir.Boruta.Oauth.Request.Base':fetch_client_authentication/1"
            },
            {
              "name": "'Elixir.Boruta.Oauth.Request.Base':check_expiration/1"
            },
            {
              "name": "'Elixir.Boruta.Oauth.Authorization.Client.Token':token_config/0"
            }
          ],
          "repo": "https://github.com/malach-it/boruta_auth",
          "packageURL": "pkg:github/malach-it/boruta_auth",
          "versions": [
            {
              "version": "5bfbe1c5443bffe71cf1bf954bbdff61327d9a83",
              "lessThan": "*",
              "versionType": "git",
              "status": "affected",
              "changes": [
                {
                  "at": "5204f88f9b2cdd9637a755337ed5f99185be5474",
                  "status": "unaffected"
                },
                {
                  "at": "69363432aa36760fc5438e4e17115d0f7c1b925a",
                  "status": "unaffected"
                }
              ]
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/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": 9.1,
          "baseSeverity": "CRITICAL",
          "attackVector": "NETWORK",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "privilegesRequired": "NONE",
          "userInteraction": "NONE",
          "vulnConfidentialityImpact": "HIGH",
          "vulnIntegrityImpact": "HIGH",
          "vulnAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "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": "2026-07-30T16:12:55.290055Z",
          "id": "CVE-2026-53431",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-294"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://cna.erlef.org/cves/CVE-2026-53431.html",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/malach-it/boruta_auth/commit/5204f88f9b2cdd9637a755337ed5f99185be5474",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/malach-it/boruta_auth/commit/69363432aa36760fc5438e4e17115d0f7c1b925a",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/malach-it/boruta_auth/security/advisories/GHSA-xjv8-vmh5-xhf6",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-53431",
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    },
    {
      "url": "https://github.com/malach-it/boruta_auth/security/advisories/GHSA-xjv8-vmh5-xhf6",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ]
}