CVE-2026-43876 AVideo: HTML Injection in notifySubscribers.json.php Allows Platform-Branded Phishing Emails to Channel Subscribers
Authenticated users can inject HTML into subscriber notification emails, enabling platform-branded phishing attacks against channel subscribers.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-43876?
CVE-2026-43876 is a medium-severity cross-site scripting vulnerability in WWBN AVideo, published on 11 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
WWBN AVideo is an open source video platform. In versions up to and including 29.0, objects/notifySubscribers.json.php takes the raw message POST parameter and passes it into sendSiteEmail(), which substitutes it directly into an HTML email template (via str_replace on the {message} placeholder) and renders it with PHPMailer::msgHTML(). There is no HTML sanitization, character escaping, or output encoding on the attacker-controlled message between $_POST['message'] and the rendered email. Any authenticated user with upload permission can therefore broadcast arbitrary HTML — phishing links, tracking pixels, CSS/UI spoofing — to every subscriber on their channel (up to 10,000 recipients per invocation). The email is sent From: the platform's configured contact address and wrapped in the site's official logo and title, so attacker-supplied HTML arrives with the appearance of an official platform communication. Commit https://github.com/WWBN/AVideo/commit/ contains an updated fix.
Weakness: CWE-79
Which versions are affected by CVE-2026-43876?
2 open source packages ship an affected version, including wwbn/avideo.
| Package | Affected | Fixed in |
|---|---|---|
wwbn/avideo Packagist | All versions to 29.0 | None |
wwbn/avideo Packagist | All versions to 29.0 | None |
How do I fix CVE-2026-43876?
No fix has been published for CVE-2026-43876 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-43876 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43876 exists.
Sources
Also known as GHSA-g9cm-rxp7-6gv5.