Tracked as CVE-2025-43400, the security defect is described as an out-of-bounds write issue in the operating system's FontParser component that could lead to a denial-of-service (DoS) condition or memory corruption. "Processing a maliciously crafted font may lead to unexpected app termination or corrupt process memory," Apple explains. According to advisories from the Hong Kong CERT and Akaoma Cybersecurity, the vulnerability can be exploited remotely, without privileges, although user interaction is required.