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Fencer Intel
medium 4.3

CVE-2026-23866 json

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 Androi…

published 6mo ago modified 14d ago also EUVD-2026-26666

cvss
4.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

Summary

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.

Patch / fix

  • Facebook WhatsApp for Android 2.26.7.10
  • Facebook WhatsApp for iOS 2.26.15.72

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6mo ago

Exploit prediction

0.47% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:F/RL:O/RC:C
CNA 3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected products

  • Facebook WhatsApp for Android
  • Facebook WhatsApp for iOS

Classification

Weakness
  • CWE-940 Improper Verification of Source of a Communication Channel

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.