CVE-2026-86917 in macOS
Summary
by MITRE • 09/15/2026
A permissions issue was addressed with additional restrictions. This issue is fixed in macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7. An app may be able to gain root privileges.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described involves a critical permissions escalation flaw within the Apple operating system ecosystem, specifically affecting versions of macOS prior to Golden Gate 27, Sequoia 15.8, and Tahoe 26.7. This issue stems from an improper implementation of access control mechanisms that govern how applications interact with privileged system resources. In a properly secured environment, application processes operate under strict sandboxing constraints designed to limit their ability to modify system files or execute commands requiring administrative rights. However, the identified flaw allows certain applications to bypass these restrictions through insufficient validation of user identity and group memberships during privilege escalation requests. This misconfiguration effectively creates an authorization gap where software that should be restricted to standard user-level operations can inadvertently trigger actions that are processed with root privileges by the operating system kernel or privileged helper tools.
From a technical perspective, this vulnerability aligns closely with CWE-269, which classifies Improper Privilege Management. The core of the issue lies in the failure to enforce least privilege principles during specific API calls or background process executions. When an application attempts to perform an action that requires elevated permissions, the system must verify not only that the user has authorized the action but also that the requesting binary is legitimately entitled to do so under current security policies. The flaw suggests that this verification step was either skipped or circumvented due to a logic error in how permission tokens were validated against the application's entitlements. Consequently, malicious actors could craft specific payloads or exploit existing software bugs within third-party applications to trigger these privileged code paths without explicit user consent for administrative changes.
The operational impact of such a vulnerability is severe, as it directly compromises the integrity and confidentiality of the entire system. By gaining root privileges, an attacker achieves full control over the macOS environment, allowing them to install persistent malware, modify critical system configurations, exfiltrate sensitive data from protected directories like /var/db or /Library/Preferences, and disable security features such as Gatekeeper or FileVault if they are configured in a way that can be overridden by root-level commands. This level of access eliminates the isolation boundaries provided by macOS's security architecture, turning any compromised application into a full system takeover vector. Furthermore, because this affects multiple major releases including Sequoia and Tahoe, it represents a widespread risk for enterprise deployments relying on these versions before patching is applied.
This type of privilege escalation is often associated with ATT&CK technique T1068, Exploitation for Privilege Escalation, where adversaries leverage software vulnerabilities to increase their access level within the host environment. It may also relate to T1548, Abuse Elevation Control Mechanism, if the exploit involves manipulating system services or helper daemons that run with higher privileges than the parent process. The presence of such a flaw indicates a need for rigorous code review and static analysis focused on authorization logic in privileged components. Security teams should prioritize applying the provided updates immediately to close this gap. Until patches are deployed, organizations can mitigate risk by enforcing strict application whitelisting policies via Mobile Device Management solutions and monitoring system logs for unusual privilege escalation events or unauthorized modifications to sensitive system files.