CVE-2026-84581 in macOS
Summary
by MITRE • 09/15/2026
A buffer overflow was addressed with improved bounds checking. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7. Mounting a maliciously crafted disk image may 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 buffer overflow condition within the macOS operating system's handling of disk images, specifically affecting components responsible for parsing and mounting file systems from such media. This type of flaw typically arises when software fails to properly validate the length of input data before copying it into a fixed-size memory buffer. In this instance, the underlying issue was addressed by implementing improved bounds checking mechanisms within the kernel-level code that processes disk image structures. The absence of these checks previously allowed an attacker to supply crafted input data exceeding the allocated buffer capacity, leading to writes beyond the intended memory boundaries. This behavior is classified under CWE-120, which denotes Buffer Copy without Checking Size of Input, a common root cause for many critical security flaws in system software where memory safety is compromised due to insufficient validation of external inputs.
The operational impact of this vulnerability is severe because it occurs at the kernel level during the mounting process of disk images. When an attacker mounts a maliciously crafted disk image, they can trigger the buffer overflow condition, potentially leading to unexpected system termination or crashes. More critically, if the exploit chain allows for arbitrary code execution rather than just denial of service, it could result in privilege escalation from user space to kernel space with full control over the operating system. Corrupting kernel memory poses a significant risk as it can destabilize the entire system, leading to data loss, unauthorized access to sensitive information stored on the disk or in memory, and potential persistence mechanisms if malicious code is injected into running processes. The ability to corrupt kernel memory specifically aligns with ATT&CK technique T1055, which covers Process Injection, as well as techniques related to privilege escalation such as T1068 Exploitation for Privilege Escalation, depending on the specific exploitation vector utilized by an adversary.
Apple has addressed this issue in macOS Golden Gate 27, macOS Sequoia 15.8, and macOS Tahoe 26.7 through enhanced bounds checking logic that ensures input data is validated against buffer limits before processing occurs. This mitigation prevents the overflow condition from being triggered even if a malicious disk image is presented to the system. To mitigate this risk in environments where updates may not be immediately applied or for systems running older versions, administrators should enforce strict policies regarding the mounting of external storage devices and disk images. Users should avoid opening disk images obtained from untrusted sources and ensure that automatic mount features are disabled if feasible within their security posture. Additionally, implementing application control solutions can help prevent unauthorized software execution that might attempt to exploit this vulnerability by crafting malicious payloads designed to trigger the buffer overflow condition during the mounting process. Regular system updates remain the most effective defense against such kernel-level vulnerabilities as they incorporate the necessary code fixes and improved memory safety checks provided by the vendor.