CVE-2026-43803 in iOS
Summary
by MITRE • 07/28/2026
An out-of-bounds write issue was addressed with improved bounds checking. This issue is fixed in iOS 26.6 and iPadOS 26.6, macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6, tvOS 26.6, visionOS 26.6, watchOS 26.6. A remote attacker may be able to cause unexpected system termination.
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Analysis
by VulDB Data Team • 07/28/2026
This vulnerability represents a critical out-of-bounds write flaw that was remediated through enhanced bounds checking mechanisms across multiple Apple operating systems. The issue manifests when applications or system processes attempt to write data beyond the allocated memory boundaries, potentially leading to unpredictable behavior and system instability. Such vulnerabilities typically arise from insufficient input validation or improper memory management during buffer operations, creating opportunities for malicious actors to exploit the weakness.
The technical nature of this vulnerability aligns with common software security flaws that fall under the CWE-787 category, which specifically addresses out-of-bounds writes in software systems. When bounds checking is inadequate, attackers can manipulate memory locations beyond intended boundaries, potentially causing system crashes or enabling more sophisticated exploitation techniques. The fix implemented by Apple involves strengthening memory validation routines to prevent unauthorized data access patterns that could lead to arbitrary code execution or denial of service conditions.
The operational impact of this vulnerability extends across Apple's entire ecosystem, affecting iOS 26.6 and iPadOS 26.6, macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6, tvOS 26.6, visionOS 26.6, and watchOS 26.6. Remote attackers can leverage this weakness to cause unexpected system termination, which may result in service disruption or create opportunities for further exploitation. The vulnerability's remote exploitability means that attackers do not require physical access to devices, making it particularly concerning for enterprise environments where mobile devices handle sensitive data.
From an attacker perspective, this issue maps to several techniques within the MITRE ATT&CK framework, particularly those involving privilege escalation and system compromise through memory corruption vulnerabilities. The remediation approach taken by Apple demonstrates a proactive security posture that addresses the root cause through improved bounds checking rather than merely patching symptoms. Organizations should prioritize deployment of these updates across all affected platforms, as the vulnerability represents a potential gateway for more sophisticated attacks targeting enterprise mobile device management systems and user data protection mechanisms.