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Arbitrary URL Processing in WhatsApp Instagram Reels AI Rich Responses
CVE-2026-23866 is an incomplete input-validation vulnerability in the handling of AI rich response messages for Instagram Reels in WhatsApp for iOS and Android. Specially crafted messages can cause a recipient’s device to process media from an arbitrary URL, including URLs that invoke operating-system-controlled custom scheme handlers. Reported affected versions are WhatsApp for iOS 2.25.8.0 through 2.26.15.72 and WhatsApp for Android 2.25.8.0 through 2.26.7.10. Reverse engineering identified an iOS path that extracts the videoURL field into a RichResponseReelItem and passes it to UIApplication.openURL after a message is tapped. This demonstrated one-click URL opening, but did not independently reproduce automatic media loading. Meta stated that it had seen no evidence of exploitation in the wild.
What it means and what to do now: patch path, interim mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
Exploitation can make a recipient’s device contact attacker-selected external resources or invoke registered custom URL scheme handlers, potentially opening applications or triggering unintended actions. Requests to attacker-controlled infrastructure may disclose the victim’s public IP address and HTTP request metadata. The behavior can support tracking, phishing, or follow-on attacks; arbitrary code execution, full device compromise, and access to private message contents are not established.
If you can’t patch tonight, do this now.
Until updates are deployed, avoid interacting with unexpected Instagram Reel previews or AI rich response messages, and educate users about suspicious rich-media messages even when received from familiar contacts. Monitor messaging-application network activity for unexpected external destinations where feasible. Avoiding taps reduces exposure to the demonstrated one-click path but is not an established defense against possible automatic media processing.
Patch, then assume compromise.
Update WhatsApp for iOS and Android to the latest vendor-patched releases through official app stores. Use versions later than iOS 2.26.15.72 and Android 2.26.7.10 to avoid the reported affected ranges. Enable automatic updates and enforce patched versions through mobile device management where applicable.
No public exploits tracked yet. Mallory keeps watching.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
16 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.