Advisory Details

August 11th, 2021

Apple macOS CoreText TTF Parsing Out-of-Bounds Read Information Disclosure Vulnerability

ZDI-21-961
ZDI-CAN-14466

CVE ID CVE-2021-30789
CVSS SCORE 3.3, (AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N)
AFFECTED VENDORS Apple
AFFECTED PRODUCTS macOS
VULNERABILITY DETAILS

This vulnerability allows remote attackers to disclose sensitive information on affected installations of Apple macOS. Interaction with the CoreText library is required to exploit this vulnerability but attack vectors may vary depending on the implementation.

The specific flaw exists within the parsing of TTF fonts. Crafted data in a TTF font can trigger a read past the end of an allocated data structure. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary 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/HT212602
DISCLOSURE TIMELINE
  • 2021-07-02 - Vulnerability reported to vendor
  • 2021-08-11 - Coordinated public release of advisory
CREDIT Mickey Jin (@patch1t) of Trend Micro
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