CVE-2026-84521 in iPadOS
Summary
by MITRE • 09/15/2026
A use after 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, visionOS 27. An app may be able to cause unexpected system termination.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described constitutes a use-after-free error, a critical class of memory safety issues that arise when software continues to reference a pointer after the memory it points to has been deallocated or freed. In this specific instance, the flaw was addressed through improved memory management protocols within the affected operating systems. This type of defect typically occurs when an object is destroyed while one or more pointers to it are still active and accessible by other parts of the application or system. When these dangling pointers are subsequently dereferenced, they access invalid memory locations, leading to undefined behavior that can compromise the stability and security of the entire computing environment.
From a technical perspective, use-after-free vulnerabilities exploit the disconnect between object lifetime management and pointer usage. An attacker who can trigger this condition may be able to manipulate how the freed memory is reallocated or interpreted by subsequent operations. This manipulation can lead to arbitrary code execution if the attacker controls the data written into the reused memory block before it is accessed again. Alternatively, as noted in the provided description, the immediate operational impact manifests as unexpected system termination. This denial of service condition disrupts normal workflow and indicates that the vulnerability has been successfully triggered but may not yet have resulted in full remote code execution due to mitigations or specific exploitation constraints within the affected components.
The scope of this vulnerability affects a wide range of Apple operating systems, including iOS 26.7, iPadOS 26.7, iOS 27, iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, and visionOS 27. The breadth of affected platforms suggests that the underlying component responsible for this memory management flaw is shared across multiple subsystems or frameworks within Apple's ecosystem. This commonality implies a systemic issue in how certain objects are handled during their lifecycle transitions, particularly in contexts where asynchronous operations or complex object graphs are involved. Users on these platforms are at risk of experiencing application crashes and potential system instability until the patches are applied.
In terms of industry standards classification, this vulnerability aligns with CWE-416, which defines use after free as a condition where software uses memory after it has been freed. This is often categorized under CWE-787 in broader contexts if it leads to out-of-bounds writes or reads due to the invalid pointer state. From an offensive security perspective, such vulnerabilities are frequently associated with MITRE ATT&CK techniques related to privilege escalation and defense evasion, as attackers leverage memory corruption flaws to bypass standard execution controls. The ability to cause system termination also touches upon availability impacts defined in the CIA triad, highlighting that even without code execution, the integrity of service delivery is compromised.
To mitigate this risk, it is imperative for users to update their devices immediately to the specified patched versions. These updates contain the corrected memory management logic that ensures pointers are properly invalidated or managed after an object's deallocation, thereby preventing access to freed memory regions. For developers and system administrators, reviewing codebases for similar patterns in custom applications running on these platforms is advisable. Implementing static analysis tools and dynamic memory checkers such as AddressSanitizer can help identify potential use-after-free conditions during the development phase. Additionally, enabling automatic security updates ensures that future patches addressing similar vulnerabilities are applied promptly, reducing the window of exposure to exploitation attempts by malicious actors seeking to destabilize systems or gain unauthorized access.