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CVE-2026-72887

Estado: AplazadaCrítica (9.8)—

Net::OAuth::Client versions before 0.32 for Perl allow the service provider to silently downgrade OAuth 1.0a to OAuth 1.0 in get_request_token.

Passing a callback to the constructor selects OAuth 1.0a. get_request_token then revokes that choice when the request token response omits oauth_callback_confirmed, with no exception, no warning and no option to require 1.0a. The access token request is built from the OAuth 1.0 message class, which has no verifier parameter, so oauth_verifier is dropped from the request even when get_access_token was passed one.

oauth_verifier is the binding that OAuth 1.0a added between the authorization step and the token exchange.

Leer descripción completaMostrar menos

An application that asked for 1.0a and gets 1.0 is open to OAuth 1.0 session fixation, where an attacker obtains a request token, has the victim authorize it, and then completes the exchange themselves, linking the victim's provider account to a session the attacker controls. No attacker action sets up the downgrade: a provider that does not confirm the callback is enough.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

OAuth downgrade (CWE-757) expone aplicaciones web Perl a session fixation. El atacante vincula cuenta victima a sesión controlada sin interacción activa, obteniendo acceso de cuenta válido y control de autorización OAuth.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Application Developer GuidanceVulnerability ScanningRestrict Web-Based ContentPrivileged Account ManagementNetwork SegmentationLimit Access to Resource Over Network

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Digitialpixies — Oauth ClientAI

CWE

Referencias

JSON original (NVD)

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{
  "id": "CVE-2026-72887",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-72887",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-08-17T16:29:01.552217Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 9.8,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 3.9
      }
    ]
  },
  "affected": [
    {
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "affectedData": [
        {
          "repo": "https://github.com/vurtdev/Net-OAuth",
          "modules": [
            "Net::OAuth::Client"
          ],
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "lessThan": "0.32",
              "versionType": "custom"
            }
          ],
          "packageURL": "pkg:cpan/Net-OAuth",
          "packageName": "Net-OAuth",
          "programFiles": [
            "lib/Net/OAuth/Client.pm"
          ],
          "collectionURL": "https://cpan.org/modules",
          "defaultStatus": "unaffected",
          "programRoutines": [
            {
              "name": "Net::OAuth::Client::get_request_token"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-08-16T14:16:54.860",
  "references": [
    {
      "url": "https://datatracker.ietf.org/doc/html/rfc5849#section-2.1",
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
    },
    {
      "url": "https://datatracker.ietf.org/doc/html/rfc5849#section-2.3",
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
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    {
      "url": "https://github.com/vurtdev/Net-OAuth/commit/fd505dac1988723ed96721657663f2e4ac731644.patch",
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
    },
    {
      "url": "https://github.com/vurtdev/Net-OAuth/security/advisories/GHSA-jh72-4qq2-8j6g",
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
    },
    {
      "url": "https://metacpan.org/release/RRWO/Net-OAuth-0.32/changes",
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2026/08/16/3",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ],
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "9b29abf9-4ab0-4765-b253-1875cd9b441e",
      "description": [
        {
          "lang": "en",
          "value": "CWE-757"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Net::OAuth::Client versions before 0.32 for Perl allow the service provider to silently downgrade OAuth 1.0a to OAuth 1.0 in get_request_token.\n\nPassing a callback to the constructor selects OAuth 1.0a. get_request_token then revokes that choice when the request token response omits oauth_callback_confirmed, with no exception, no warning and no option to require 1.0a. The access token request is built from the OAuth 1.0 message class, which has no verifier parameter, so oauth_verifier is dropped from the request even when get_access_token was passed one.\n\noauth_verifier is the binding that OAuth 1.0a added between the authorization step and the token exchange. An application that asked for 1.0a and gets 1.0 is open to OAuth 1.0 session fixation, where an attacker obtains a request token, has the victim authorize it, and then completes the exchange themselves, linking the victim's provider account to a session the attacker controls. No attacker action sets up the downgrade: a provider that does not confirm the callback is enough."
    }
  ],
  "lastModified": "2026-08-26T16:51:19.490",
  "sourceIdentifier": "9b29abf9-4ab0-4765-b253-1875cd9b441e"
}