CVE-2021-30889 in macOS
Summary
by MITRE • 08/25/2021
A buffer overflow issue was addressed with improved memory handling. 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 arbitrary code execution.
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Analysis
by VulDB Data Team • 05/22/2025
The buffer overflow vulnerability identified as CVE-2021-30889 represents a critical security flaw in Apple's operating systems that could enable remote code execution through web content. This vulnerability resides within the memory management subsystem of macOS Monterey, iOS, iPadOS, watchOS, and tvOS platforms, specifically affecting versions prior to the security updates released in late 2021. The flaw demonstrates characteristics consistent with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The vulnerability's exploitation pathway involves processing maliciously crafted web content that triggers improper memory handling during content rendering or parsing operations.
The technical implementation of this vulnerability stems from inadequate input validation and memory allocation practices within Apple's web rendering engines. When legitimate web content is processed through these affected systems, the buffer overflow occurs during memory allocation for web page elements, potentially allowing attackers to overwrite critical memory segments including return addresses, function pointers, or other control structures. This type of vulnerability falls under the ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation could enable attackers to execute arbitrary code with the privileges of the affected application or system process. The memory corruption resulting from this buffer overflow creates a predictable attack surface that adversaries can leverage to gain unauthorized access to system resources.
The operational impact of CVE-2021-30889 extends beyond individual device compromise to potentially enable large-scale attacks against vulnerable Apple ecosystem deployments. Organizations relying on Apple devices for business operations face significant risk exposure, particularly in environments where users may encounter malicious web content through email attachments, web browsing, or enterprise applications. The vulnerability's presence in multiple Apple platforms including mobile devices, wearables, and television systems creates a broad attack surface that adversaries can exploit across various device types. Security professionals must consider this vulnerability as part of broader threat modeling exercises, particularly when evaluating the security posture of environments where Apple devices serve as endpoints for sensitive data processing or network access.
Mitigation strategies for CVE-2021-30889 center on immediate deployment of the security updates released by Apple, which include macOS Monterey 12.0.1, iOS 15.1, iPadOS 15.1, watchOS 8.1, and tvOS 15.1. Organizations should implement comprehensive patch management procedures to ensure all affected devices receive the necessary updates promptly. Network administrators should consider implementing web filtering solutions and content sanitization measures as additional protective layers against potentially malicious web content. The vulnerability's remediation aligns with security best practices outlined in NIST SP 800-128 for vulnerability management and patch deployment. System administrators should also monitor for indicators of compromise related to this vulnerability and establish incident response procedures to address potential exploitation attempts. Regular security assessments and penetration testing should be conducted to verify that the patches have been successfully deployed and that no residual vulnerabilities remain within the affected systems.