Advisory Details

May 12th, 2026

Apple Safari Web Inspector WebCore Style Resolver Use-After-Free Remote Code Execution Vulnerability

ZDI-26-312
ZDI-CAN-28879

CVE ID CVE-2026-28955
CVSS SCORE 7.5, AV:N/AC:H/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 WebCore style resolver in Web Inspector. The issue results from the lack of validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the browser process.

ADDITIONAL DETAILS Apple has issued an update to correct this vulnerability. More details can be found at:
https://support.apple.com/en-ca/127111
DISCLOSURE TIMELINE
  • 2026-03-05 - Vulnerability reported to vendor
  • 2026-05-12 - Coordinated public release of advisory
  • 2026-05-12 - Advisory Updated
CREDIT wac
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