CVE-2026-84561 in iOS
Summary
by MITRE • 09/15/2026
A double free issue was addressed with improved memory management. This issue is fixed in iOS 26.7 and iPadOS 26.7, iOS 27 and iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, 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 involves a critical double free error within the operating system's core components, specifically affecting iOS, iPadOS, macOS, tvOS, visionOS, and watchOS platforms. A double free condition occurs when an application attempts to deallocate a block of memory that has already been freed by another part of the program or previously in its own execution flow. This flaw represents a severe violation of proper memory management protocols, where the system fails to track the allocation state of heap objects accurately. In the context of modern operating systems like those developed by Apple, such errors are particularly dangerous because they can lead to arbitrary code execution with kernel privileges if exploited successfully. The issue was addressed through improved memory management techniques that likely include enhanced tracking mechanisms for allocated blocks and stricter validation checks before deallocation occurs.
From a technical perspective, this vulnerability aligns closely with CWE-415, which defines double free as freeing the same pointer more than once, leading to undefined behavior. When an attacker triggers this condition within a privileged process or kernel space, they can manipulate the heap metadata structures that manage memory allocation. By carefully crafting inputs that cause the system to release the same memory address twice, an adversary can corrupt internal data structures used by the operating system for managing resources. This corruption can result in unexpected system termination, causing denial of service conditions where critical services crash or the entire device reboots unexpectedly. More critically, if the corrupted heap metadata is manipulated correctly, it may allow an attacker to achieve arbitrary read and write primitives, which are foundational steps toward gaining full control over the affected system.
The operational impact of this vulnerability extends beyond simple application crashes. Because the fix was deployed across a wide range of Apple operating systems including iOS 26.7, iPadOS 26.7, macOS Sequoia 15.8, and others, it indicates that the flaw existed in widely used system libraries or frameworks accessible to third-party applications. An app with appropriate permissions could potentially exploit this issue to escalate privileges from a sandboxed environment to the kernel level. This escalation path is consistent with ATT&CK technique T1068, which covers exploitation for privilege escalation. Once an attacker gains kernel-level access, they can bypass security controls such as System Integrity Protection (SIP), install persistent malware, or exfiltrate sensitive user data without detection. The ability to corrupt kernel memory also poses a risk of stability issues across the entire device ecosystem, affecting not just the malicious app but all other running processes and services.
Mitigation strategies primarily rely on applying the provided software updates immediately upon availability for each respective platform. For end-users, this means ensuring that iOS, iPadOS, macOS, tvOS, visionOS, and watchOS devices are updated to their latest supported versions as listed in the advisory. Developers should review their applications for any custom memory management code that might inadvertently trigger similar conditions during testing phases. Implementing static analysis tools and dynamic debugging techniques can help identify potential double free scenarios before deployment. Additionally, leveraging modern programming languages with automatic garbage collection or strict ownership models like Rust can reduce the likelihood of such low-level memory errors occurring in new software developments. Security teams should monitor for indicators of compromise related to heap corruption and kernel panics that may signal active exploitation attempts against unpatched systems.