CVE-2025-43380 is a vulnerability identified in Apple macOS that stems from an out-of-bounds write condition triggered during file parsing. The root cause is insufficient input validation, which allows malformed or specially crafted files to cause the application processing them to terminate unexpectedly. This behavior results in a denial-of-service (DoS) condition affecting the availability of the affected application. The vulnerability is classified under CWE-787 (Out-of-bounds Write), indicating that the software writes data outside the boundaries of allocated memory, potentially corrupting memory and causing crashes. The issue affects multiple macOS versions prior to the patched releases: macOS Sequoia 15.7.2, macOS Tahoe 26.1, and macOS Sonoma 14.8.2. Exploitation requires local access with low privileges (AV:L, PR:L), no user interaction (UI:N), and the scope is unchanged (S:U). The CVSS v3.1 base score is 5.5, reflecting a medium severity primarily due to the impact on availability (A:H) without confidentiality or integrity loss. No known exploits have been reported in the wild, suggesting limited active exploitation. The vulnerability could be triggered by parsing malicious files, potentially delivered via removable media, email attachments, or local file transfers. The fix involves improved input validation to prevent out-of-bounds writes and ensure robust memory handling during file parsing.

For European organizations, the primary impact of CVE-2025-43380 is on the availability of macOS applications that parse files, which could lead to denial-of-service conditions. This may disrupt business operations, especially in environments where Apple devices are integral to workflows, such as creative industries, software development, and certain government or research institutions. Although the vulnerability does not compromise confidentiality or integrity, repeated or targeted exploitation could degrade user productivity and system reliability. The requirement for local access and low privileges limits the risk of remote exploitation, but insider threats or malware with local execution capabilities could leverage this flaw. Organizations relying on macOS for critical infrastructure or services should be aware of potential service interruptions. Additionally, the lack of user interaction needed for exploitation means that automated processes parsing files could be vulnerable without user awareness. The absence of known exploits in the wild reduces immediate risk but does not eliminate the need for timely patching.

To mitigate CVE-2025-43380, European organizations should prioritize updating affected macOS systems to the latest patched versions: Sequoia 15.7.2, Tahoe 26.1, or Sonoma 14.8.2. System administrators should enforce strict update policies and verify patch deployment across all Apple devices. Restricting file parsing to trusted sources can reduce exposure; for example, disabling automatic processing of files from unverified origins or scanning files with endpoint security solutions before opening. Employing application whitelisting and sandboxing can limit the impact of crashes caused by malformed files. Monitoring logs for unexpected application terminations may help detect exploitation attempts. Additionally, educating users about the risks of opening files from unknown or untrusted sources can reduce the likelihood of triggering the vulnerability. For environments with high security requirements, consider isolating macOS systems handling untrusted files or using virtualized environments to contain potential crashes.