ZDI-26-312: Apple Safari Web Inspector WebCore Style Resolver Use-After-Free Remote Code Execution Vulnerability

Published May 12, 2026
·
Updated

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.

Other sources

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 ZDI has assigned a CVSS rating of 7.5. The following CVEs are assigned: CVE-2026-28955.

ZDI

Affected Software

1 affected component
Apple Safari

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Patch ZDI-26-312
  2. Compensating control

    Reduce exposure by preventing users from visiting untrusted websites or opening untrusted files, since user interaction is required (malicious page or file) to exploit the Apple Safari Web Inspector WebCore Style Resolver use-after-free RCE vulnerability.

Event History

May 12, 2026
Advisory Published
via ZDI·12:00 AM
Data Sourced
via ZDI·12:00 AM
DescriptionSeverityAffected Software
Advisory Published
via ZDI·05:00 AM

Frequently Asked Questions

1

What is the severity of ZDI-26-312?

The severity of ZDI-26-312 is high, as it allows for remote code execution on affected installations of Apple Safari.

2

How do I fix ZDI-26-312?

To fix ZDI-26-312, users should update their Apple Safari to the latest version provided by Apple.

3

What software is affected by ZDI-26-312?

ZDI-26-312 affects Apple Safari web browser installations.

4

What type of attack is associated with ZDI-26-312?

ZDI-26-312 is associated with a use-after-free vulnerability that can lead to remote code execution.

5

Is user interaction required to exploit ZDI-26-312?

Yes, user interaction is required as the target must visit a malicious website to exploit ZDI-26-312.

Contact

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