CVE-2026-28854 in macOS
Summary
by MITRE • 10/20/2026
The issue was addressed with additional app bundle integrity checks. This issue is fixed in macOS Golden Gate 27. A maliciously modified app may not be prevented from launching.
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Analysis
by VulDB Data Team • 10/20/2026
This vulnerability pertains to a critical failure in the application sandboxing and code signing enforcement mechanisms within Apple's macOS operating system, specifically affecting versions prior to the implementation of macOS Golden Gate 27. The core technical flaw lies in the integrity verification process for app bundles, which are complex directory structures containing executable binaries, resources, and metadata required for an application to function correctly on macOS systems. Under normal circumstances, when a user attempts to launch an application, the operating system performs rigorous checks to ensure that the binary has not been tampered with since it was signed by its developer. These checks typically involve verifying cryptographic signatures against Apple's trusted certificate authorities and ensuring that all components within the bundle match their expected hashes. However, in this specific instance, a logic error or missing validation step allowed maliciously modified app bundles to bypass these security controls. By exploiting this gap, an attacker could alter the contents of an application package while preserving its valid signature structure enough to trick the system into believing it is authentic and unmodified.
The operational impact of this vulnerability is severe because it undermines one of the primary defense-in-depth layers provided by macOS against malware execution. When a maliciously modified app launches successfully, it operates with the same permissions as any other legitimate application installed on the user's machine. This means that attackers can inject arbitrary code into trusted applications or replace critical components within an app bundle to execute payloads without triggering standard security alerts associated with unsigned or improperly signed software. Such behavior aligns closely with MITRE ATT&CK techniques related to Masquerading, where adversaries modify legitimate files to appear as something else, and potentially Impair Defenses by disabling or bypassing system-level protections like Gatekeeper. The ability to launch modified apps effectively neutralizes the trust model that relies on code signing integrity checks, allowing for persistent access, data exfiltration, or further lateral movement within a compromised environment without immediate detection by standard endpoint security tools.
To mitigate this risk, organizations and individual users must ensure their macOS systems are updated to version Golden Gate 27 or later, where the additional app bundle integrity checks have been implemented to close this specific gap in verification logic. It is crucial for system administrators to enforce automatic updates through mobile device management solutions or centralized patching strategies to guarantee that all endpoints receive these critical security patches promptly. Additionally, while software updates are the primary remediation step, organizations should complement this with behavioral monitoring and application whitelisting policies where feasible. By restricting execution to only known-good applications and monitoring for anomalies in file system changes within app directories, defenders can add an extra layer of protection against exploitation attempts that might target unpatched systems or attempt to bypass integrity checks through alternative vectors. Regular audits of installed software and verification of code signatures using command-line tools such as codesign can also help identify potentially compromised applications before they are executed by end users.