CVE-2021-30890 in macOS
Summary
by MITRE • 08/25/2021
A logic issue was addressed with improved state management. This issue is fixed in macOS Monterey 12.0.1, iOS 15.1 and iPadOS 15.1, watchOS 8.1, tvOS 15.1. Processing maliciously crafted web content may lead to universal cross site scripting.
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Analysis
by VulDB Data Team • 07/10/2025
The vulnerability identified as CVE-2021-30890 represents a significant security flaw in Apple's operating systems that stems from inadequate state management within web content processing mechanisms. This logic issue specifically affects the handling of web content that could be manipulated by malicious actors to execute universal cross-site scripting attacks. The vulnerability exists across multiple Apple platforms including macOS Monterey, iOS, iPadOS, watchOS, and tvOS, indicating a systemic problem in how these systems manage web rendering states. The flaw allows attackers to craft specially designed web content that bypasses existing security controls, potentially enabling unauthorized access to sensitive user data and system resources. The issue was particularly concerning because it could be exploited through standard web browsing activities, making it accessible to attackers without requiring specialized tools or extensive technical knowledge. The vulnerability's classification as a logic issue aligns with CWE-254, which addresses weaknesses in security design that result from inadequate state management or insufficient access control mechanisms. This particular flaw demonstrates how seemingly minor state management problems can create substantial security risks when they affect core system components responsible for processing external content.
The technical exploitation of this vulnerability occurs when users interact with maliciously crafted web content that leverages the improper state handling to execute cross-site scripting attacks across multiple platforms simultaneously. This universal nature of the exploit means that successful attacks can affect all affected Apple operating systems without requiring platform-specific variations in the malicious payload. The flaw likely involves improper validation of web content states during rendering processes, allowing attackers to manipulate the execution flow of web applications and potentially gain access to sensitive system resources or user data. The attack vector primarily involves web-based content delivery, making it particularly dangerous as users can be compromised simply by visiting malicious websites or interacting with compromised web applications. Security researchers identified that the vulnerability stems from insufficient state validation mechanisms that should have prevented the execution of unauthorized code sequences. The fix implemented by Apple in versions 12.0.1, 15.1, and 8.1 respectively addresses the root cause by improving how the systems maintain and validate state information during web content processing, thereby preventing the conditions that enabled the cross-site scripting attacks. This remediation approach aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where attackers could leverage the vulnerability to execute malicious scripts in the context of the user's web browser.
The operational impact of CVE-2021-30890 extends beyond simple web browsing risks to potentially compromise user privacy and system integrity across multiple Apple devices. Organizations using Apple devices for business operations face elevated risks of data breaches, unauthorized access to corporate resources, and potential escalation to more severe security incidents. The vulnerability's ability to affect multiple platforms simultaneously increases the attack surface and makes it more challenging for security teams to implement effective mitigations. Users who regularly access the internet through Apple devices are particularly vulnerable, as the attack can occur without their explicit knowledge or consent. The exploit's potential for persistent access means that once compromised, systems could remain vulnerable until the security update is applied. Security professionals should note that this vulnerability demonstrates the importance of state management in web security frameworks and highlights how subtle logic flaws can create widespread security implications. The fix requires timely deployment across all affected platforms, which can be challenging for organizations with large device fleets or those operating in environments where automatic updates are not feasible. This vulnerability serves as a reminder of the critical importance of maintaining current security patches and the potential consequences of delayed remediation in mobile and desktop operating systems. Organizations should implement monitoring for suspicious web traffic patterns and ensure all Apple devices receive the necessary security updates to prevent exploitation of this universal cross-site scripting vulnerability.