CVE-2026-23866 Server-side request forgery in WhatsApp for Android

Medium 4.3 Published 1 May 2026 Updated 1 May 2026

Incomplete validation in WhatsApp allowed attackers to trigger media processing from arbitrary URLs, potentially invoking OS handlers on victim devices.

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-2026-23866?

CVE-2026-23866 is a medium-severity server-side request forgery vulnerability in Facebook WhatsApp for Android, published on 1 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

Incomplete validation of AI rich response messages for Instagram Reels in WhatsApp for iOS v2.25.8.0 to v2.26.15.72 and WhatsApp for Android v2.25.8.0 to v2.26.7.10 could have allowed a user to trigger processing of media content from an arbitrary URL on another user’s device, including triggering OS-controlled custom URL scheme handlers. We have not seen evidence of exploitation in the wild.

Weakness: CWE-940

Which versions are affected by CVE-2026-23866?

It affects 1 product.

Products include Whatsapp Whatsapp.

How do I fix CVE-2026-23866?

No fix has been published for CVE-2026-23866 yet. Limit exposure of the affected software until one is available.

Upgrade, and send outbound requests through an allow-list that blocks internal addresses. More about Server-side request forgery.

Is CVE-2026-23866 being exploited?

There is no known exploitation of CVE-2026-23866 in the wild and no public exploit code.

Sources

Also known as GHSA-4x7f-p792-g362.