CVE-2026-20616 is a vulnerability identified in Apple macOS and related operating systems that arises from an out-of-bounds write condition when processing USD (Universal Scene Description) files. The root cause is insufficient bounds checking during the parsing or handling of these files, which can lead to memory corruption. This memory corruption manifests as an unexpected termination of applications that process the maliciously crafted USD files, effectively causing a denial-of-service (DoS) condition. The vulnerability affects multiple Apple platforms, including macOS Tahoe 26.3, macOS Sonoma 14.8.4, iOS 18.7.5, iPadOS 18.7.5, and visionOS 26.3. The CVSS v3.1 base score is 6.5, indicating a medium severity level, with an attack vector of network (remote), low attack complexity, no privileges required, but requiring user interaction to open or process the malicious file. The scope is unchanged, and the impact is limited to availability, with no confidentiality or integrity impacts reported. Apple has fixed this vulnerability by implementing improved bounds checking to prevent out-of-bounds writes. There are no known exploits in the wild at the time of publication. The vulnerability is classified under CWE-787 (Out-of-bounds Write), a common memory safety issue that can lead to crashes or potentially more severe impacts if exploited further. The vulnerability could be triggered by convincing a user to open or process a malicious USD file, which might be delivered via email, web download, or other file transfer methods.

The primary impact of CVE-2026-20616 is denial of service through unexpected application termination, which can disrupt user productivity and potentially affect critical workflows on Apple devices. While the vulnerability does not directly compromise confidentiality or integrity, repeated or targeted exploitation could degrade system reliability and availability. For organizations relying heavily on Apple ecosystems, especially those using USD files in workflows such as 3D graphics, animation, or AR/VR content creation, this vulnerability could interrupt operations. In environments where availability is critical, such as healthcare, finance, or industrial control systems using Apple devices, the impact could be significant. Although no privilege escalation or remote code execution is indicated, the vulnerability could be used as part of a multi-stage attack chain if combined with other exploits. The lack of known exploits reduces immediate risk, but the medium severity score and ease of triggering via user interaction warrant timely remediation.

Organizations should prioritize applying the security updates released by Apple for macOS Tahoe 26.3, macOS Sonoma 14.8.4, iOS 18.7.5, iPadOS 18.7.5, and visionOS 26.3 to ensure the vulnerability is patched. Beyond patching, organizations should implement strict email and file filtering to detect and block suspicious USD files or attachments. User awareness training should emphasize caution when opening files from untrusted sources, particularly USD files which may be less commonly scrutinized. Employ application whitelisting or sandboxing techniques to limit the impact of potential crashes caused by malicious files. Monitoring application logs for unexpected terminations related to USD file processing can help detect exploitation attempts. For environments using USD files extensively, consider validating and sanitizing USD content before processing. Incident response plans should include procedures for handling denial-of-service incidents caused by malformed files. Finally, maintain up-to-date backups to recover quickly from any disruption caused by exploitation.