CVE-2026-84575 in iOS
Summary
by MITRE • 09/15/2026
An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 27 and iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, tvOS 27, visionOS 27, watchOS 27. Processing a maliciously crafted file may lead to unexpected app termination.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described constitutes an out-of-bounds write flaw within the core processing logic of Apple's operating systems, specifically affecting iOS, iPadOS, macOS, tvOS, visionOS, and watchOS versions prior to their respective security updates. This type of memory corruption error typically arises when a software application writes data beyond the boundaries of allocated memory buffers. In this specific instance, the issue was addressed by implementing improved bounds checking mechanisms within the file processing subsystems. The root cause lies in insufficient validation of input parameters or buffer sizes before writing operations are executed against external files. When an attacker provides a maliciously crafted file that triggers these unchecked write paths, the application attempts to store data at memory addresses outside its designated allocation space. This behavior is classified under CWE-787: Out-of-bounds Write in the Common Weakness Enumeration framework, which highlights the critical nature of buffer boundary validation as a fundamental security control for preventing memory corruption vulnerabilities.
The operational impact of this vulnerability centers on the potential for denial of service through application termination rather than immediate remote code execution. Processing a maliciously crafted file can cause the affected application to crash unexpectedly due to segmentation faults or access violations triggered by writing to invalid memory regions. While out-of-bounds writes are often associated with privilege escalation and arbitrary code execution, in this context, the primary observed consequence is instability leading to app termination. This disruption affects user availability and system reliability across multiple platforms including mobile devices, desktops, and wearable technology. The vulnerability aligns with ATT&CK technique T1059: Command and Scripting Interpreter if exploited via script-based file processing or T1203: Exploitation for Client Execution if the crafted file is designed to trigger specific execution paths before crashing. However, given the description emphasizes termination rather than code execution, it primarily represents a reliability risk that could be leveraged in denial-of-service attacks against services relying on these applications.
Mitigation strategies require immediate application of the provided security updates across all affected platforms including iOS 27 and later, iPadOS 27 and later, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, tvOS 27, visionOS 27, and watchOS 27. These updates contain the necessary patches that enforce strict bounds checking during file processing operations to prevent writes beyond allocated memory limits. Organizations should prioritize patching endpoints running these operating systems to eliminate the attack surface associated with untrusted file ingestion. Additionally, implementing defense-in-depth measures such as sandboxing applications that process external files can limit the impact of any potential exploitation attempts. Security teams should also monitor for anomalous application crashes or termination events in logs which may indicate probing activity targeting this specific memory corruption flaw. Regular security awareness training regarding handling unknown or suspicious file types remains essential to reduce the risk of users inadvertently triggering such vulnerabilities through social engineering vectors.