Is CVE-2026-23866 in the CISA KEV catalog?

No. CVE-2026-23866 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-23866?

CVE-2026-23866 has a CVSS v3 base score of 4.3 (MEDIUM).

What is the EPSS score for CVE-2026-23866?

CVE-2026-23866 has an EPSS score of 0.46% (37th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-23866?

No published fix for CVE-2026-23866 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-23866

MEDIUM

4.3

CVSS v3

NVD

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.

CWE-940

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityLow

IntegrityNone

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Exploit Intelligence

0.46%probability of exploitation in 30 days

37thpercentile

Low risk: more likely to be exploited than 37% of all known CVEs.

References

Vendor Advisory1

whatsapp.com

Third-Party Advisory1

facebook.com

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Markdown

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-11.