Advisory Details

February 16th, 2022

Apple macOS libFontParser TTF Font Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability

ZDI-22-377
ZDI-CAN-13835

CVE ID CVE-2021-30771
CVSS SCORE 7.8, (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)
AFFECTED VENDORS Apple
AFFECTED PRODUCTS macOS
VULNERABILITY DETAILS

This vulnerability allows remote attackers to execute arbitrary code on affected installations of Apple macOS. Interaction with the libFontParser 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 write past the end of an allocated data structure. 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-us/HT212529
DISCLOSURE TIMELINE
  • 2021-05-12 - Vulnerability reported to vendor
  • 2022-02-16 - Coordinated public release of advisory
CREDIT Mickey Jin (@patch1t) of Trend Micro
BACK TO ADVISORIES