CVE-2026-84558 in macOS
Summary
by MITRE • 09/15/2026
A double free issue was addressed with improved memory management. This issue is fixed in macOS Golden Gate 27. An app may be able to cause unexpected system termination.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described involves a critical memory management flaw known as a double-free error, which has been identified and remediated within the macOS operating system, specifically addressed in version Golden Gate build 27. A double free occurs when an application attempts to deallocate or release a block of memory that has already been freed by another part of the program or previously released code path. This condition violates fundamental principles of safe memory handling and can lead to severe instability within the operating environment. The root cause typically stems from logic errors in software where reference counting mechanisms fail, pointers are not nullified after deallocation, or concurrent threads access shared resources without proper synchronization primitives such as mutexes or locks.
From a technical perspective, this flaw falls under the category of CWE-415, which is defined as Double Free. This type of vulnerability is particularly dangerous because it can corrupt internal data structures maintained by memory allocators like malloc and free in C-based environments. When an allocator receives instructions to release already freed memory, its metadata becomes inconsistent, potentially allowing attackers or malicious processes to manipulate heap layouts. In the context of macOS, this corruption can trigger assertions within system services or cause undefined behavior that manifests as application crashes. The specific impact noted is unexpected system termination, which indicates that the vulnerability affects core components or privileged processes where stability is paramount for overall system integrity and user experience.
The operational impact of this double free issue extends beyond simple application instability. While the immediate symptom is an app causing a crash, sophisticated exploitation could potentially lead to arbitrary code execution if the memory corruption allows overwriting function pointers or control flow data structures such as return addresses on the stack or vtable entries in object-oriented implementations. Although the current report highlights termination rather than remote code execution, the underlying mechanism remains a high-risk vector for privilege escalation or denial of service attacks against system services running with elevated privileges. The fix implemented in macOS Golden Gate 27 likely involves rigorous validation checks before memory release, ensuring that pointers are verified as valid and not previously freed, thereby restoring safe memory management practices across affected components.
Mitigation strategies primarily rely on the deployment of the provided software update to ensure all systems run version 27 or later where this logic error has been corrected. For developers and security teams monitoring their environments, it is advisable to review any custom applications that interact with these system APIs for similar patterns of improper memory handling. Utilizing static analysis tools and dynamic debugging instruments like AddressSanitizer can help identify potential double-free conditions during the development phase before deployment. Furthermore, adhering to secure coding standards such as those outlined in CWE-415 guidelines ensures that future software iterations maintain robustness against heap corruption vulnerabilities. The ATT&CK framework categorizes this type of exploitation under techniques related to memory corruption and privilege escalation, emphasizing the need for continuous monitoring and patch management to mitigate risks associated with low-level system flaws.