CVE-2026-43785 in iOS
Summary
by MITRE • 09/15/2026
A permissions issue was addressed with additional restrictions. This issue is fixed in iOS 27 and iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, tvOS 27, visionOS 27. An app may be able to modify a file it only had permission to read.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described constitutes an improper access control flaw within the operating system's file management subsystems for iOS, iPadOS, macOS, tvOS, and visionOS platforms. Specifically, this issue allows applications that are granted read-only permissions on certain files or directories to inadvertently or maliciously modify those same resources. This behavior violates the fundamental principle of least privilege, where software should only possess the minimum levels of access necessary to perform its intended function. By bypassing these restrictions, an app can alter data it was explicitly denied write access to, leading to potential integrity violations and unauthorized state changes within the system or user data stores.
From a technical perspective, this flaw likely stems from insufficient validation checks during file I/O operations or race conditions in how permission contexts are enforced by the kernel or sandboxing mechanisms. When an application requests read access, the operating system's security framework should strictly enforce that boundary throughout the lifecycle of the open file descriptor. However, due to the identified defect, there exists a pathway through which write permissions can be implicitly granted or bypassed. This could occur if the underlying API does not correctly map user-space permission flags to kernel-level enforcement rules, or if temporary elevation privileges are mishandled during specific system interactions. Such weaknesses often arise from complex inter-process communication patterns or shared resource management logic that fails to re-evaluate permissions before every write operation.
The operational impact of this vulnerability is significant for both end-users and enterprise environments relying on these platforms. An attacker who exploits this flaw could modify critical configuration files, alter user-generated content without authorization, or corrupt system settings by injecting malicious data into read-only locations. This capability undermines the integrity guarantees provided by the operating system's sandboxing architecture. In a multi-tenant environment or when dealing with sensitive personal information, such unauthorized modifications can lead to data tampering, privilege escalation if combined with other vulnerabilities, and a breakdown of trust in application boundaries. It effectively neutralizes one layer of defense against malicious apps that might otherwise be contained by strict read-only constraints.
This issue aligns closely with Common Weakness Enumeration (CWE) category CWE-269, which covers Improper Privilege Management, and more specifically CWE-732, describing Incorrect Permission Assignment for Critical Resource. In the context of the MITRE ATT&CK framework, this vulnerability facilitates techniques related to Defense Evasion by allowing an adversary to bypass file integrity monitoring or modify system configurations without triggering standard permission denial alerts. It also supports Persistence mechanisms if critical startup files are altered, and can contribute to Privilege Escalation if the modified resources control access to higher-level system functions.
To mitigate this risk, users must ensure that their devices are updated to the latest available versions of iOS 27, iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, tvOS 27, and visionOS 27. These updates contain the necessary code changes to enforce stricter permission boundaries during file operations. Developers should also review their applications for any reliance on implicit permissions or assumptions about file system behavior that might exploit similar gaps in other systems. Implementing rigorous input validation and adhering strictly to declared entitlements can further reduce exposure to such access control flaws. Regular security audits of application code against these updated platform APIs are recommended to ensure continued compliance with modern security standards.