Description

An out-of-bounds read was addressed with improved bounds checking. This issue is fixed in iOS 27 and iPadOS 27, macOS Golden Gate 27, tvOS 27, visionOS 27, watchOS 27. Processing a maliciously crafted font may result in the disclosure of process memory.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "6.5",
  "pubDate": "2026-09-14T21:17:35.193Z",
  "pubdate": "2026-09-14T21:17:35.193Z",
  "executiveSummary": "This vulnerability is an out-of-bounds read flaw within the font-processing logic across multiple Apple operating systems, including iOS 27, iPadOS 27, macOS Golden Gate 27, tvOS 27, visionOS 27, and watchOS 27.\nThe vulnerability occurs when the system parses a maliciously crafted font file, leading to memory access outside the intended buffer boundaries.\nThe primary security impact is the unauthorized disclosure of sensitive process memory, which may contain cryptographic keys, session tokens, or other private data residing within the application's memory space.\nExploitation requires an attacker to convince a user or system process to parse a specifically manipulated font file.\nThe risk implication is significant as memory disclosure vulnerabilities are frequently utilized as a primitive to bypass security features such as Address Space Layout Randomization (ASLR), potentially facilitating further exploitation chains.\nThis issue has been addressed by implementing improved bounds checking during the parsing phase to ensure that memory read operations remain within authorized limits.",
  "technicalDetails": "The vulnerability resides within the font rendering or parsing subsystem responsible for interpreting font file formats (e.g., TrueType, OpenType). The root cause is an insufficient validation of internal data structures during the processing of font metadata or glyph tables, leading to an out-of-bounds read.\nWhen a maliciously crafted font file is provided to the system, the parser fails to properly verify the size and offset values defined within the file's headers or specific data blocks. During the parsing sequence, the software accesses memory offsets that extend beyond the allocated buffer for the font data.\nThe attack flow follows a sequential process: 1) An attacker creates a malformed font file where specific length fields are manipulated to misrepresent the actual size of the data blocks. 2) The font file is delivered to the target, often via web content, document viewing, or applications that leverage the OS-level font rendering engine. 3) The operating system's font parser attempts to load or render the font. 4) Due to the lack of strict bounds checking, the parser proceeds to read adjacent memory locations outside the current heap or stack buffer.\nThe post-exploitation impact includes the leakage of arbitrary memory contents from the process context executing the font parser. If the parser operates in a privileged process, the leaked data could include sensitive information from the kernel or higher-privileged processes. This leakage is often used by attackers to determine the memory layout of the target binary, effectively neutralizing ASLR protections.\nThis vulnerability exists in the core font processing components shared across iOS 27, iPadOS 27, macOS Golden Gate 27, tvOS 27, visionOS 27, and watchOS 27. It does not require user authentication for local triggers, though the attack surface is generally gated by the application's requirement to parse an externally provided or embedded font file."
}