CVE-2024-27876 in iOS
Summary
by MITRE • 09/17/2024
A race condition was addressed with improved locking. This issue is fixed in iOS 17.7 and iPadOS 17.7, iOS 18 and iPadOS 18, macOS Sequoia 15, macOS Sonoma 14.7, macOS Ventura 13.7, visionOS 2. Unpacking a maliciously crafted archive may allow an attacker to write arbitrary files.
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Analysis
by VulDB Data Team • 04/04/2026
The vulnerability identified as CVE-2024-27876 represents a critical race condition flaw that existed within Apple's operating systems, specifically affecting iOS, iPadOS, macOS, and visionOS versions prior to their respective security updates. This type of vulnerability occurs when multiple processes or threads attempt to access and modify shared resources simultaneously, creating opportunities for unpredictable behavior and potential security breaches. The race condition was particularly concerning because it could be exploited through the process of unpacking maliciously crafted archives, which are commonly used in various attack vectors including phishing campaigns and malware distribution.
The technical flaw stems from inadequate synchronization mechanisms during file extraction operations, where proper locking protocols were insufficient to prevent concurrent access to critical system resources. When an attacker crafts a specially designed archive file, the vulnerable system's unpacking routine may execute multiple operations in rapid succession without proper coordination between threads or processes. This lack of proper locking allows an attacker to manipulate the extraction process and potentially overwrite system files or create arbitrary files in locations where they would not normally be permitted to write. The vulnerability falls under the CWE-362 category of race conditions, which is classified as a fundamental concurrency issue that has been consistently identified as a high-risk security flaw in software development practices.
The operational impact of this vulnerability extends beyond simple file manipulation capabilities, as it could potentially enable privilege escalation attacks and system compromise. Attackers leveraging this race condition could craft archive files that, when processed by vulnerable systems, would allow them to write files to protected system directories or replace existing system components with malicious counterparts. This capability aligns with ATT&CK technique T1059.007 for command and scripting interpreter, where adversaries might use such vulnerabilities to establish persistence or execute malicious code within the target environment. The vulnerability affects multiple Apple platforms simultaneously, indicating a systemic issue within the file handling libraries and system call implementations across the Apple ecosystem.
The fix implemented by Apple addresses this issue through improved locking mechanisms that ensure proper synchronization during archive extraction processes. This mitigation approach specifically targets the root cause by implementing robust mutex locks or similar concurrency control primitives that prevent multiple threads from accessing shared resources simultaneously during critical operations. The security updates released for iOS 17.7 and iPadOS 17.7, along with iOS 18 and iPadOS 18, macOS Sequoia 15, macOS Sonoma 14.7, macOS Ventura 13.7, and visionOS 2, demonstrate Apple's proactive approach to addressing this race condition. Organizations and users must ensure their systems are updated to these versions to mitigate the risk of exploitation, as the vulnerability could be leveraged by threat actors to gain unauthorized access to affected systems. The remediation approach also reinforces the importance of proper software development practices in preventing concurrency-related security issues that could have far-reaching implications across multiple operating system versions and device types within the Apple ecosystem.