CVE-2026-86910 in macOS
Summary
by MITRE • 09/15/2026
A permissions issue was addressed with improved path validation. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7. An application may be able to access restricted files.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described involves a critical failure in the operating system's file access control mechanisms, specifically within the path validation logic of Apple's macOS environment. This flaw allows an unauthorized process or user context to bypass intended security restrictions and gain read or write access to sensitive system files that are typically protected by strict permission boundaries. The root cause lies in insufficient sanitization or verification of file paths provided during application execution, which permits attackers to traverse directory structures or exploit relative path ambiguities to reach restricted locations outside the designated sandbox or user home directories. This type of flaw is classically categorized under CWE-284 Improper Access Control and often relates to CWE-73 External Control of File Name or Path, indicating a failure in validating input before using it for file system operations.
From an operational perspective, this vulnerability poses significant risks to data integrity and confidentiality on affected macOS systems including versions prior to Golden Gate 27, Sequoia 15.8, and Tahoe 26.7. An attacker who can execute arbitrary code or trick a privileged application into processing maliciously crafted file paths could potentially exfiltrate sensitive user data such as credentials, personal documents, or system configuration files. In more severe scenarios involving privilege escalation vectors, this flaw might serve as an initial foothold for further exploitation of higher-level security controls. The impact is particularly acute in multi-user environments where one user might attempt to access another user's private data by exploiting the path validation weakness through a shared application or service that processes file inputs without adequate isolation checks.
This vulnerability aligns with several tactics within the MITRE ATT&CK framework, notably T1083 File and Directory Discovery, which describes techniques used for enumerating files on a target system to identify valuable data targets. Additionally, it relates to T1552 Unsecured Credentials if the accessed restricted files contain stored authentication tokens or private keys. The lack of proper path validation also touches upon principles outlined in CWE-434 Unsafe Upload or Save of Executable File if the vulnerability allows writing malicious payloads into system directories that are later executed by privileged processes, thereby facilitating persistent access or privilege escalation.
To mitigate this risk, it is imperative to apply the latest security updates provided by Apple for macOS Golden Gate 27, Sequoia 15.8, and Tahoe 26.7 immediately upon availability. These patches include enhanced path validation routines that rigorously check file paths against allowed directories and enforce strict boundary checks before granting access. Administrators should also ensure that applications are running with the principle of least privilege, minimizing the potential impact if a vulnerability is exploited. Furthermore, implementing application sandboxing where possible can restrict an application's ability to interact with arbitrary parts of the filesystem regardless of path validation flaws. Regular auditing of file system permissions and monitoring for unusual access patterns to sensitive directories can also help detect exploitation attempts early in the attack lifecycle.