Apple Safari jsToWasm IC Entrypoint Type Confusion Remote Code Execution Vulnerability

October 28th, 2026
ZDI-26-830 ZDI-CAN-34401

CVE ID

CVE-2026-86974

CVSS Score

8.8 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected Vendors

Apple

Affected Products

Safari

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Apple Safari. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.

The specific flaw exists within the implementation of jsToWasm IC entrypoint. By performing actions in JavaScript, an attacker can trigger a type confusion condition. An attacker can leverage this vulnerability to execute code in the context of the current process.

Additional Details

Apple has issued an update to correct this vulnerability. More details can be found at:
https://support.apple.com/en-ca/149527

Disclosure Timeline

  • 2026-09-17 - Vulnerability reported to vendor
  • 2026-10-28 - Coordinated public release of advisory
  • 2026-10-28 - Advisory Updated

Credit

Hossein Lotfi (@hosselot) of TrendAI Zero Day Initiative

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