CVE-2026-33731

AVideo has an Authorize.Net Webhook Signature Bypass that Enables Wallet Balance Inflation via Forged Payment Data

• Wallet balance inflation: Attacker credits arbitrary amounts to any user's wallet without corresponding payment, bypassing the payment gateway's actual charge amount.
• Premium content access: Inflated wallet balance allows purchasing all paid/premium video content without real payment.
• Subscription fraud: By including plans_id in forged metadata, the attacker can activate premium subscriptions (webhook.php:86-134) without corresponding payment.
• Financial loss: Platform owner loses revenue from fraudulently accessed premium content and services.

CVE-2026-33731 has a CVSS score of 6.5 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (29.0); upgrading removes the vulnerable code path.

Kodem intelligence

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1. Reject webhooks with invalid signatures unconditionally, the transaction lookup should only be used for data enrichment after signature validation passes:

// webhook.php line 33, FIX: reject on invalid signature alone
if (!$parsed['signatureValid']) {
    _error_log('[Authorize.Net webhook] Bad signature');
    http_response_code(401);
    echo 'invalid signature';
    exit;
}

2. Use API-fetched values as authoritative, in webhook.php lines 44-55, invert the precedence so $txnInfo values always override payload values:

// Always prefer API-fetched values over payload values
if (!empty($txnInfo['users_id'])) {
    $analysis['users_id'] = (int)$txnInfo['users_id'];
}
if (isset($txnInfo['amount'])) {
    $analysis['amount'] = (float)$txnInfo['amount'];
}

3. Check isApproved before processing, add a gate before processSinglePayment():

if (!$analysis['isApproved']) {
    _error_log('[Authorize.Net webhook] Transaction not approved');
    http_response_code(400);
    echo 'transaction not approved';
    exit;
}

1. What is CVE-2026-33731? CVE-2026-33731 is a medium-severity security vulnerability in wwbn/avideo (composer), affecting versions <= 28.0. It is fixed in 29.0.
2. How severe is CVE-2026-33731? CVE-2026-33731 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of wwbn/avideo are affected by CVE-2026-33731? wwbn/avideo (composer) versions <= 28.0 is affected.
4. Is there a fix for CVE-2026-33731? Yes. CVE-2026-33731 is fixed in 29.0. Upgrade to this version or later.
5. Is CVE-2026-33731 exploitable, and should I be worried? Whether CVE-2026-33731 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-33731 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-33731? Upgrade wwbn/avideo to 29.0 or later.

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