CVE-2026-43793 in macOS
Summary
by MITRE • 07/28/2026
An issue existed in the handling of environment variables. This issue was addressed with improved validation. This issue is fixed in macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, macOS Tahoe 26.6. An app may be able to cause unexpected system termination.
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Analysis
by VulDB Data Team • 07/28/2026
This vulnerability relates to insufficient validation of environment variables within the operating system's processing pipeline, representing a classic security weakness that can lead to system instability and potential privilege escalation scenarios. The flaw exists in how the system handles environment variable parsing and execution contexts, allowing malicious applications to manipulate these variables in ways that were not properly anticipated by the original design. According to CWE-20, this vulnerability stems from inadequate input validation, specifically concerning environment variables that are typically used to configure application behavior and system parameters. The issue manifests when applications can craft environment variable values that trigger unexpected behavior during system processing, potentially leading to abrupt termination of critical system processes or services.
The technical implementation of this vulnerability allows an attacker to inject maliciously formatted environment variables that cause the system to interpret these inputs incorrectly, resulting in unexpected system termination or crashes. This represents a denial-of-service condition that can be exploited by applications running with appropriate privileges or through social engineering techniques that trick users into executing malicious code. The exploitation mechanism typically involves carefully crafted environment variable contents that trigger buffer overflows, invalid memory access patterns, or improper resource handling within the system's environment variable processing routines. Attackers leveraging this vulnerability can potentially cause cascading failures in system services or applications that depend on proper environment variable handling, creating a pathway for more severe attacks including privilege escalation or persistent system compromise.
The operational impact of this vulnerability extends beyond simple system crashes to include potential data loss, service disruption, and reduced system availability across affected macOS versions. Systems running macOS Sequoia 15.7.8, macOS Sonoma 14.8.8, and macOS Tahoe 26.6 are not immune to this issue, as these versions contain the flawed environment variable handling logic that was addressed through improved validation mechanisms. Organizations and users operating on these platforms face increased risk of system instability, particularly in environments where multiple applications interact with shared system resources or where applications may have elevated privileges. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter usage, as malicious environment variables can be used to execute unintended commands or trigger unexpected system behaviors that bypass normal security controls.
The mitigation strategy for this vulnerability involves applying the patched versions of macOS operating systems where improved validation has been implemented to prevent malformed environment variable inputs from causing system termination. System administrators should prioritize deployment of these updates across all affected systems, particularly in enterprise environments where multiple applications may interact with system processes through environment variables. Additional defensive measures include implementing strict environment variable validation at application level, monitoring for unusual process termination patterns, and establishing robust patch management procedures to ensure timely deployment of security fixes. The fix addresses the underlying weakness by introducing enhanced input sanitization, parameter validation, and proper error handling within the environment variable processing pipeline, ensuring that malformed inputs do not lead to system instability or unexpected behavior in legitimate applications.