How severe is CVE-2026-23866?

CVE-2026-23866 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2026-23866 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-23866?

CVE-2026-23866 primarily affects Whatsapp. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-23866?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-23866 have an EU (EUVD) identifier?

Yes. CVE-2026-23866 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26666.

When was CVE-2026-23866 published?

CVE-2026-23866 was published on 2026-05-01 and last updated on 2026-06-17.

CVE-2026-23866

CVE-2026-23866 is a medium-severity vulnerability in Whatsapp with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-940.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-26666
Weakness: CWE-940
Affected product: Whatsapp
Published: 2026-05-01
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2026-23866?: 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.
How severe is CVE-2026-23866?: CVE-2026-23866 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2026-23866 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-23866?: CVE-2026-23866 primarily affects Whatsapp. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-23866?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-23866 have an EU (EUVD) identifier?: Yes. CVE-2026-23866 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-26666.
When was CVE-2026-23866 published?: CVE-2026-23866 was published on 2026-05-01 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:whatsapp:whatsapp:*:*:*:*:*:android:*:*
cpe:2.3:a:whatsapp:whatsapp:*:*:*:*:*:iphone_os:*:*

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