GHSA-c8h8-vq34-9fw2
WWBN AVideo: Stored XSS via unescaped Gallery category description
Packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| Packagist | WWBN/AVideo | <= 29.0 | no fix listed |
Details
As written in the advisory (Markdown source, shown as plain text).
### Summary
AVideo stores category descriptions from user input and later renders `category_description` as raw HTML in the Gallery view. A user who can create or edit
categories can store JavaScript in a category description, which executes when another user views the affected Gallery/category page.
This is a stored XSS in the category `description` field, separate from previously fixed XSS issues in video titles or comments.
### Details
Source:
`objects/categoryAddNew.json.php`
```php
$objCat->setDescription($_POST['description']);
Storage setter:
objects/category.php
public function setDescription($description)
{
$this->description = $description;
}
```
Sink:
`plugin/Gallery/view/mainAreaCategory.php`
```
<div id="categoryDescription<?php echo $duid; ?>" style="display: none;"><?php echo $videos[0]['category_description']; ?></div>
```
The value is rendered without `htmlspecialchars()`, `htmlentities()`, `HTMLPurifier`, or equivalent output encoding.
### PoC
Prerequisites:
- AVideo current master / v29.0
- User account with permission to create or edit categories
- Gallery plugin/view enabled
- At least one video assigned to the affected category
Steps:
1. Log in as a user who can create or edit categories.
2. Create or edit a category.
3. Set the category description to:
```
<img src=x onerror=alert(document.domain)>
```
4. Save the category.
5. Assign at least one video to that category.
6. Open the Gallery/category page that renders the category section.
7. The payload is inserted into the page as raw HTML and JavaScript executes.
### Impact
An attacker with category edit permission can execute JavaScript in the browser of users or administrators who view the affected Gallery/category page. This can
be used to perform actions as the victim, steal same-origin data accessible to JavaScript, or abuse administrative UI actions if an administrator views the
malicious category.
### Recommended fix
- Sanitize category descriptions on input with the same HTML policy used for video descriptions, or store plain text only.
- Encode on output:
```php
echo htmlspecialchars($videos[0]['category_description'], ENT_QUOTES, 'UTF-8');
```
- If limited HTML is intended, run the description through HTMLPurifier before storage or before render.
- Add regression tests for category description rendering in Gallery views.
References
External links from the advisory. They lead to third-party sites.