CVE-2021-30952 in macOS
Summary
by MITRE • 08/25/2021
An integer overflow was addressed with improved input validation. This issue is fixed in tvOS 15.2, macOS Monterey 12.1, Safari 15.2, iOS 15.2 and iPadOS 15.2, watchOS 8.3. Processing maliciously crafted web content may lead to arbitrary code execution.
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Analysis
by VulDB Data Team • 03/07/2026
The vulnerability identified as CVE-2021-30952 represents a critical integer overflow flaw that exists within Apple's web rendering and processing components across multiple operating systems. This issue stems from inadequate input validation mechanisms that fail to properly handle excessively large integer values during web content processing operations. The vulnerability specifically affects Apple's tvOS, macOS Monterey, Safari, iOS, and watchOS platforms, indicating a widespread impact across the company's ecosystem. The integer overflow occurs when the system processes maliciously crafted web content that contains oversized numerical values, which can cause the application to behave unpredictably and potentially execute arbitrary code.
The technical nature of this vulnerability aligns with CWE-190, which describes integer overflow conditions where an integer value exceeds the maximum representable value for its data type. This flaw operates at the intersection of web browser security and system-level memory management, where the processing of web content triggers a cascade of operations that can be exploited to manipulate system memory. When attackers craft web pages containing specifically designed integer values, the overflow can overwrite adjacent memory locations, potentially allowing malicious code execution. The vulnerability's exploitation pathway involves web-based attack vectors that leverage the browser's rendering engine to trigger the integer overflow condition during normal web browsing operations.
The operational impact of CVE-2021-30952 extends beyond simple privilege escalation, as it provides attackers with a mechanism to achieve arbitrary code execution within the context of the affected applications. This capability represents a significant threat to user security and system integrity, particularly given that web browsers serve as primary attack surfaces for many cyber threats. The vulnerability's exploitation can lead to complete system compromise, data theft, or deployment of additional malware payloads. Organizations and individual users face heightened risk when browsing untrusted websites, as the attack surface includes not just malicious web pages but also potentially compromised web applications that may be exploited through this integer overflow condition. The vulnerability's presence in multiple Apple platforms suggests that attackers can target users across different device types, from mobile devices to desktop computers and television systems.
Mitigation strategies for CVE-2021-30952 primarily focus on immediate system updates and patches provided by Apple. Users should prioritize updating to the affected versions mentioned in the advisory, including tvOS 15.2, macOS Monterey 12.1, Safari 15.2, iOS 15.2, and iPadOS 15.2, along with watchOS 8.3. Security administrators should implement network-based protections such as web application firewalls and content filtering systems that can detect and block malicious web content before it reaches end-user devices. Browser security configurations should be enhanced with additional sandboxing measures and strict content security policies that limit the execution of potentially malicious code. The vulnerability's classification under ATT&CK technique T1059.004 for script-based attacks and T1566 for social engineering highlights the need for comprehensive security awareness training to prevent users from inadvertently accessing malicious web content. Organizations should also consider implementing network monitoring solutions that can detect unusual patterns of web traffic that might indicate exploitation attempts, while maintaining regular vulnerability assessments to identify potential additional attack vectors that could leverage similar integer overflow conditions.