Advisory Details

January 25th, 2019

Apple Safari CSSFontFace Use-After-Free Remote Code Execution Vulnerability

ZDI-19-123
ZDI-CAN-7204

CVE ID CVE-2019-6234
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 WebKit
VULNERABILITY DETAILS

This vulnerability allows remote attackers to execute arbitrary code on vulnerable 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 handling of fonts. 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 current process.

ADDITIONAL DETAILS Apple has issued an update to correct this vulnerability. More details can be found at:
https://support.apple.com/kb/HT201222
DISCLOSURE TIMELINE
  • 2018-09-03 - Vulnerability reported to vendor
  • 2019-01-25 - Coordinated public release of advisory
CREDIT G. Geshev from MWR Labs
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