CVE-2023-41990 in macOS
Summary
by MITRE • 09/12/2023
The issue was addressed with improved handling of caches. This issue is fixed in macOS Ventura 13.2, iOS 15.7.8 and iPadOS 15.7.8, watchOS 9.3, tvOS 16.3, iOS 16.3 and iPadOS 16.3, macOS Big Sur 11.7.9, macOS Monterey 12.6.8. Processing a font file may lead to arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited against versions of iOS released before iOS 15.7.1.
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Analysis
by VulDB Data Team • 04/22/2025
The vulnerability identified as CVE-2023-41990 represents a critical security flaw in Apple's operating systems that manifests through improper cache handling during font file processing. This issue specifically affects multiple Apple platforms including iOS, iPadOS, macOS, watchOS, and tvOS across various versions. The vulnerability stems from insufficient validation and sanitization of font files, particularly when these files are processed through system caches that store frequently accessed data for performance optimization. When a maliciously crafted font file is encountered during normal system operations, the flawed cache handling mechanism can lead to arbitrary code execution, allowing attackers to gain unauthorized access to affected systems.
The technical implementation of this vulnerability involves the exploitation of cache mechanisms that Apple employs to improve system performance when processing font files. According to CWE classification, this vulnerability aligns with CWE-129, which addresses improper validation of array indices, and CWE-787, which covers out-of-bounds write conditions. The flaw occurs when the system processes font files that contain specially crafted data structures designed to manipulate cache contents beyond their intended boundaries. Attackers can leverage this vulnerability through various attack vectors including malicious email attachments, web downloads, or compromised applications that utilize font rendering capabilities. The ATT&CK framework categorizes this as a privilege escalation technique under T1068, where initial access leads to code execution with elevated privileges.
The operational impact of CVE-2023-41990 extends beyond simple code execution, as it represents a sophisticated attack surface that could enable full system compromise. The fact that Apple has acknowledged active exploitation attempts against iOS versions prior to 15.7.1 demonstrates the real-world threat level of this vulnerability. Systems running affected versions are particularly vulnerable because they lack the improved cache handling mechanisms that were implemented in the patched releases. The exploitation chain typically begins with a user interacting with a malicious font file, which triggers the vulnerable cache processing routine, ultimately resulting in arbitrary code execution. This vulnerability affects both enterprise and consumer environments, as font files are commonly encountered through various legitimate system functions, making the attack surface broad and difficult to fully mitigate through user education alone.
Apple's response to this vulnerability included comprehensive updates across all affected platforms, with specific versions receiving patches including macOS Ventura 13.2, iOS 15.7.8, watchOS 9.3, tvOS 16.3, and the corresponding updates for macOS Big Sur and Monterey. The mitigation strategy focuses on improved cache validation and sanitization procedures that prevent malicious data from corrupting system memory during font processing operations. Organizations should prioritize immediate deployment of these security updates across all affected devices, particularly those running older iOS versions that have not yet received the necessary patches. Additional mitigations include implementing network-level controls to block suspicious font file downloads, disabling unnecessary font rendering capabilities in applications, and monitoring system logs for unusual cache behavior that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches across all system components, as font processing routines, though seemingly benign, can provide sophisticated attack vectors when improperly secured.