CVE-2026-43728 in macOS
Summary
by MITRE • 07/28/2026
This issue was addressed through improved state management. This issue is fixed in macOS Tahoe 26.6. An attacker may be able to modify the state of the Keychain.
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Analysis
by VulDB Data Team • 07/29/2026
This vulnerability represents a critical weakness in the macOS Keychain subsystem's state management mechanisms, specifically targeting the integrity of stored cryptographic credentials and sensitive information. The flaw allows malicious actors to manipulate the internal state of the Keychain service, potentially enabling unauthorized modifications to stored passwords, certificates, and other security tokens without proper authentication or authorization. Such an issue fundamentally undermines the trust model that Keychain relies upon for secure credential storage and retrieval operations.
The technical implementation defect stems from inadequate validation and control mechanisms within the Keychain's state transition management system. When applications or processes interact with the Keychain service, they should maintain strict state consistency to prevent unauthorized modifications. However, the vulnerability creates opportunities for attackers to inject malicious state changes that can persist across system sessions, potentially allowing for credential theft, privilege escalation, or persistent access to protected resources. This weakness aligns with CWE-362, which addresses concurrent execution use of a resource, and CWE-284, concerning improper access control mechanisms.
The operational impact of this vulnerability extends beyond simple credential compromise, as it can enable sophisticated attack patterns that leverage the Keychain's trusted status within the operating system. An attacker who successfully exploits this state management flaw could potentially modify keychain entries to redirect authentication flows, insert malicious credentials, or manipulate existing stored information in ways that would go undetected by standard monitoring systems. The vulnerability particularly affects scenarios where applications rely on Keychain for authentication tokens, API keys, or certificate management, as the modified state could persist across reboots and system updates.
Mitigation strategies should focus on implementing robust access controls and state validation mechanisms within Keychain operations. System administrators should ensure immediate deployment of macOS Tahoe 26.6 patches that address this specific state management issue. Additional protective measures include implementing application whitelisting to restrict which processes can interact with Keychain services, enabling enhanced monitoring for unauthorized Keychain modifications, and conducting regular audits of stored credentials to detect potential tampering. Organizations should also consider implementing multi-factor authentication mechanisms that reduce the impact of credential compromise even when Keychain integrity is breached.
The remediation approach demonstrates the importance of proper state management in security-critical systems as outlined in MITRE ATT&CK framework's credential access techniques, specifically targeting the persistence and privilege escalation capabilities that such vulnerabilities enable. This vulnerability type represents a classic case where insufficient input validation and state consistency checks create exploitable pathways for attackers to manipulate core security services. The fix implemented in macOS Tahoe 26.6 likely includes enhanced validation of state transitions, stricter access controls on Keychain operations, and improved integrity checking mechanisms to prevent unauthorized modifications to the Keychain's internal state management structures.