CVE-2025-43380 is a vulnerability identified in Apple macOS operating systems that arises from an out-of-bounds write condition during file parsing. The root cause is insufficient input validation, which allows crafted files to trigger memory corruption leading to unexpected application termination. This vulnerability is classified under CWE-787, which refers to out-of-bounds writes that can corrupt memory and cause crashes or unpredictable behavior. The issue affects multiple macOS versions before the release of Sequoia 15.7.2, Sonoma 14.8.2, and Tahoe 26.1, where Apple has implemented improved input validation to mitigate the risk. The CVSS v3.1 base score is 5.5, indicating a medium severity level. The attack vector is local (AV:L), requiring low complexity (AC:L) and low privileges (PR:L), with no user interaction (UI:N) needed. The impact is limited to availability (A:H), with no confidentiality or integrity impact. No known exploits have been reported in the wild, but the vulnerability could be leveraged to cause denial-of-service conditions by crashing applications that parse maliciously crafted files. This could disrupt workflows or critical services relying on affected macOS applications. The vulnerability highlights the importance of robust input validation in file parsing routines to prevent memory corruption issues.

The primary impact of CVE-2025-43380 is on the availability of applications running on affected macOS systems. Exploitation can cause unexpected application termination, leading to denial-of-service conditions. This can disrupt user productivity, critical business operations, or services that depend on stable application behavior. Since the vulnerability requires local access and low privileges, attackers with limited system access could still exploit it to cause disruptions. Although it does not compromise confidentiality or integrity, repeated or targeted exploitation could degrade system reliability and user trust. Organizations relying heavily on macOS for critical infrastructure, development environments, or end-user computing may experience operational interruptions. The absence of known exploits in the wild reduces immediate risk, but the medium severity score suggests timely patching is necessary to prevent potential future attacks.

To mitigate CVE-2025-43380, organizations should immediately apply the security updates provided by Apple in macOS Sequoia 15.7.2, Sonoma 14.8.2, and Tahoe 26.1 or later. Beyond patching, restrict the sources of files that applications parse to trusted origins to reduce exposure to maliciously crafted files. Implement application whitelisting and sandboxing to limit the impact of crashes and isolate affected applications. Monitor system and application logs for abnormal termination patterns that could indicate exploitation attempts. Educate users about the risks of opening untrusted files, especially in environments where local access is shared or less controlled. For critical systems, consider deploying endpoint detection and response (EDR) solutions capable of detecting anomalous process crashes or memory corruption behaviors. Regularly review and update incident response plans to address potential denial-of-service scenarios caused by such vulnerabilities.