WWBN AVideo is an open source video platform. Versions prior to 29.0 contain an unauthenticated Reflected XSS vulnerability through AVideo YouTubeAPI Gallery Pagination. The $_GET['search'] query parameter is concatenated directly into the href attribute of two pagination links in plugin/YouTubeAPI/gallerySection.php (lines 67 and 74) with no htmlspecialchars, no urlencode, and no allow-list check. An injected <script> element is then extracted by the AVideo Layout plugin and concatenated into a single trailing inline script block at the bottom of the page, where the browser executes it. Any unauthenticated attacker can lure a victim into following a crafted URL to execute arbitrary JavaScript under the AVideo origin, which can read non-HttpOnly cookies and issue authenticated AJAX requests as the victim, and when the victim is an administrator, it can perform any cookie-authenticated admin action (create user, promote to admin, change configuration, install plugin), escalating a single click into full administrative takeover. This issue has been patched by this commit: https://github.com/WWBN/AVideo/commit/f50fc033b7adb36f1ffd6640e7826468bdafdec3.

Affected: Packagist: WWBN/AVideo

# Unauthenticated Reflected XSS via `$_GET['search']` in AVideo YouTubeAPI Gallery Pagination

## Summary

A reflected Cross-Site Scripting vulnerability (CWE-79) in the AVideo YouTubeAPI plugin allows any unauthenticated attacker to execute arbitrary JavaScript in a victim's browser session when the victim follows a crafted URL. The `$_GET['search']` query parameter is concatenated directly into the `href` attribute of two pagination links in `plugin/YouTubeAPI/gallerySection.php` (lines 67 and 74) with no `htmlspecialchars`, no `urlencode`, and no allow-list check. An injected `<script>` element is then extracted by the AVideo Layout plugin and concatenated into a single trailing inline script block at the bottom of the page, where the browser executes it.

## Details

`plugin/YouTubeAPI/gallerySection.php` renders the YouTubeAPI plugin's gallery section on the AVideo homepage (and every page that includes `plugin/Gallery/view/mainArea.php`) when the API plugin is enabled with `showGallerySection=true` (the default). The pagination block at lines 67 and 74 builds the previous-page and next-page `<a>` elements by string-interpolating `$_GET['search']` directly:

```php // plugin/YouTubeAPI/gallerySection.php:67 <a href="<?php echo "{$global['webSiteRootURL']}page/".($_GET['page']-1)."?pageToken={$object->prevPageToken}&search=".(@$_GET['search']); ?>" ...>

// plugin/YouTubeAPI/gallerySection.php:74 <a href="<?php echo "{$global['webSiteRootURL']}page/".($_GET['page']+1)."?…