This vulnerability allows remote attackers to disclose sensitive information on affected installations of Apple macOS. 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 GetFDIndex function in libFontParser. Crafted data in an OTF 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.