CVE-2026-65398 in iOS
Summary
by MITRE • 09/15/2026
An out-of-bounds access issue 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. An app may be able to cause unexpected system termination or corrupt kernel memory.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described constitutes a critical out-of-bounds access flaw within the core operating systems of Apple's ecosystem, specifically affecting iOS, iPadOS, macOS, tvOS, visionOS, and watchOS versions prior to their respective twenty-seventh major releases. This type of memory corruption issue arises when software attempts to read from or write to a memory location that is outside the boundaries of the intended buffer or data structure. In the context of kernel-level operations, such as those implied by the potential for kernel memory corruption, this flaw represents a severe breach of system integrity. The root cause typically involves insufficient validation of array indices, pointer arithmetic errors, or failure to check length parameters before accessing allocated memory regions. When an application triggers this condition, it forces the operating system's memory management unit to handle access requests that violate established security boundaries, leading to undefined behavior within the kernel space.
The operational impact of this vulnerability is significant due to its potential for both denial of service and privilege escalation. As noted in the advisory, a maliciously crafted application can exploit this flaw to cause unexpected system termination, which manifests as a crash or reboot of the device. This constitutes a local denial-of-service attack where an unprivileged user-space process disrupts the availability of critical system services by corrupting kernel memory structures such as page tables, file descriptors, or execution stacks. More critically, if the out-of-bounds access allows for arbitrary read and write operations within kernel space, it can be leveraged to bypass security mitigations like Kernel Address Space Layout Randomization (KASLR) and Data Execution Prevention (DEP). By carefully crafting memory writes, an attacker could overwrite function pointers or return addresses, thereby achieving code execution with kernel-level privileges. This effectively grants the attacker full control over the device, enabling data exfiltration, persistence mechanisms, and further lateral movement within connected networks.
From a classification perspective, this vulnerability aligns closely with Common Weakness Enumeration (CWE) identifiers such as CWE-125 Out-of-bounds Read and CWE-787 Out-of-bounds Write, depending on the specific nature of the memory access violation. These weaknesses are fundamental categories in software security that describe failures to verify array bounds or pointer validity before performing memory operations. In terms of offensive security frameworks, this exploit vector maps directly to MITRE ATT&CK techniques related to Privilege Escalation and Defense Evasion. Specifically, it relates to mechanisms where attackers manipulate kernel memory to bypass access controls or execute arbitrary code in a protected environment. The ability to corrupt kernel memory places this vulnerability at the highest severity tier within threat modeling exercises, as it undermines the fundamental trust boundary between user applications and the operating system core.
Mitigation strategies for this issue are primarily centered around software updates and defensive programming practices. For end-users and enterprise administrators, the immediate remediation is to apply the latest security patches provided in iOS 27, iPadOS 27, macOS Golden Gate 27, tvOS 27, visionOS 27, and watchOS 27. These updates contain the improved bounds checking logic that prevents the out-of-bounds access from occurring during runtime execution. For developers creating applications for these platforms, it is imperative to implement rigorous input validation and ensure that all memory allocations are accompanied by strict boundary checks before any read or write operations are performed. Utilizing static analysis tools and dynamic fuzzing techniques can help identify similar vulnerabilities in custom codebases before deployment. Furthermore, enabling system-level protections such as Pointer Authentication Codes (PAC) on supported Apple Silicon devices adds an additional layer of defense against exploitation attempts that rely on overwriting memory addresses to hijack control flow.