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CVE-2026-23866: Incomplete validation of AI rich response messages for Instagram Reels in WhatsApp for iOS v2.25.8.0 to v2.26.

25
Routine
MEDIUM 4.3UPGRADEUPGRADE

CVE-2026-23866 is a medium-severity flaw (CVSS 4.3) affecting whatsapp, whatsapp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

  • No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score4.3 (Medium)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededLow
User interactionNone
EPSS exploit chance0.5% (top 59%)
CISA exploited listNo
WeaknessCWE-940
Published2026-05-01
Last modified2026-10-26
Publisher (CNA): Facebook, Inc. · Vendor: whatsapp

Share: LinkedIn · X · Reddit

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

whatsapp whatsapp UPGRADE
Affected: >= 2.25.8.0 and <= 2.26.7.10
Fixed in: newer than 2.26.7.10
Safe to downgrade to: a release before 2.25.8.0
1. Check installed version
apt-cache policy whatsapp || rpm -q whatsapp || whatsapp --version
2. UPGRADE to newer than 2.26.7.10 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade whatsapp
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade whatsapp
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 2.25.8.0 (Debian / Ubuntu)
apt-cache madison whatsapp sudo apt install whatsapp=<VERSION_BEFORE_2.25.8.0> sudo apt-mark hold whatsapp
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list whatsapp sudo dnf downgrade whatsapp-<VERSION_BEFORE_2.25.8.0> sudo dnf versionlock add whatsapp
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
whatsapp whatsapp UPGRADE
Affected: >= 2.25.8.0 and <= 2.26.15.72
Fixed in: newer than 2.26.15.72
Safe to downgrade to: a release before 2.25.8.0
1. Check installed version
apt-cache policy whatsapp || rpm -q whatsapp || whatsapp --version
2. UPGRADE to newer than 2.26.15.72 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade whatsapp
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade whatsapp
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 2.25.8.0 (Debian / Ubuntu)
apt-cache madison whatsapp sudo apt install whatsapp=<VERSION_BEFORE_2.25.8.0> sudo apt-mark hold whatsapp
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list whatsapp sudo dnf downgrade whatsapp-<VERSION_BEFORE_2.25.8.0> sudo dnf versionlock add whatsapp
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-23866?

whatsapp: upgrade to newer than 2.26.7.10; whatsapp: upgrade to newer than 2.26.15.72. Exact commands for each OS are on this page.

Is CVE-2026-23866 being exploited?

CVE-2026-23866 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-23866 affect?

CVE-2026-23866 affects whatsapp, whatsapp. Severity is medium (CVSS 4.3). 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 ar

How urgent is CVE-2026-23866?

Priority 25/100. No elevated risk signals yet.

Software pages

Android vulnerabilities · iOS vulnerabilities · WhatsApp vulnerabilities

Related CVEs

References

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