{
  "affected": [
    {
      "package": {
        "ecosystem": "Packagist",
        "name": "spomky-labs/otphp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "11.4.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-1284",
      "CWE-369"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-18T20:45:47Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "## Summary\n\nThe `digits` parameter parsed from a provisioning URI is validated only with a lower bound (`$value \u003e 0`) and has no upper bound (`src/OTP.php:353-357`). OTP generation computes `$code % (10 ** $this-\u003egetDigits())` (`src/OTP.php:283`). When `digits` is large enough that `10 ** digits` overflows PHP\u0027s integer range and the `(int)` cast yields `0` (around `digits \u003e= 40` on 64-bit PHP 8.x), the modulo operand becomes `0` and PHP raises a `DivisionByZeroError`.\n\n## Impact\n\n`OTPHP\\Factory::loadFromProvisioningUri()` forwards the attacker-controlled `digits` query value to `setParameter(\u0027digits\u0027, $value)`, so a hostile URI such as `otpauth://totp/Alice?secret=JBSWY3DPEHPK3PXP\u0026digits=50` produces an OTP object whose `at()`, `now()`, and `verify()` all throw `DivisionByZeroError`. Because `DivisionByZeroError` extends `Error` (not `Exception`), callers that guard OTP generation with a `catch (\\Exception)` do not catch it, turning a malformed URI into an unhandled fatal error (denial of service of the verification path).\n\nMeasured threshold on PHP 8.3: `digits = 30` works, `digits \u003e= 40` throws `DivisionByZeroError: Modulo by zero`.\n\n## Affected component\n\n- `src/OTP.php:353-357` \u2014 `digits` parameter callback (no upper bound)\n- `src/OTP.php:283` \u2014 `$code % (10 ** $this-\u003egetDigits())`\n\n## Proof of concept\n\n```php\nuse OTPHP\\Factory;\nuse OTPHP\\InternalClock;\n\n$otp = Factory::loadFromProvisioningUri(\n    \u0027otpauth://totp/Alice?secret=JBSWY3DPEHPK3PXP\u0026digits=50\u0027,\n    new InternalClock()\n);\n$otp-\u003eat(0); // DivisionByZeroError: Modulo by zero (escapes catch (\\Exception))\n```\n\n## Remediation\n\nEnforce a sane upper bound on `digits` in the parameter validation callback (e.g. reject values above 8\u201310, the practical range for OTPs) so that an out-of-range value is rejected with a documented exception instead of producing an object that fails later with an uncatchable `Error`.",
  "id": "GHSA-g7m4-839x-ch6v",
  "modified": "2026-06-18T20:45:48Z",
  "published": "2026-06-18T20:45:47Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/Spomky-Labs/otphp/security/advisories/GHSA-g7m4-839x-ch6v"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/spomky-labs/otphp/GHSA-g7m4-839x-ch6v.yaml"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Spomky-Labs/otphp"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "spomky-labs/otphp: Unbounded digits parameter in a provisioning URI triggers an uncaught DivisionByZeroError in OTP generation"
}