CVE-2026-43686 in iPadOS
Summary
by MITRE • 09/15/2026
A use-after-free issue was addressed with improved memory management. This issue is fixed in iOS 26.7 and iPadOS 26.7, iOS 27 and iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, tvOS 27, visionOS 27, watchOS 27. Connecting to a malicious NFS server may lead to kernel memory corruption.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability described constitutes a critical use-after-free condition within the network file system client implementation of Apple operating systems. This class of error occurs when a program continues to use a pointer after it has been freed, leading to undefined behavior that can range from application crashes to arbitrary code execution. In this specific instance, the flaw resides in how memory buffers are managed during interactions with Network File System servers. When an iOS or iPadOS device connects to a malicious NFS server, the system processes incoming data packets without adequately verifying whether previously allocated kernel memory structures have been properly deallocated and nullified. This lapse allows for the reuse of freed memory regions that may still be referenced by active pointers within the network stack.
The technical root cause lies in the race condition or logic error during the lifecycle management of socket buffers associated with NFS connections. As data is received from a remote server, the kernel allocates temporary structures to handle packet parsing and state updates. If these structures are freed prematurely while still being accessed by concurrent threads handling different aspects of the connection, an attacker can manipulate the timing or content of incoming packets to exploit this window. By crafting specific NFS responses that trigger premature deallocation followed by immediate access, a malicious actor can corrupt kernel memory. This corruption is not limited to simple denial-of-service scenarios; it provides a pathway for privilege escalation and remote code execution within the kernel space, which holds the highest level of trust on the operating system.
From an operational perspective, this vulnerability poses a severe risk to devices that connect to untrusted or compromised network environments. Since NFS is often used in enterprise and development settings where users might connect to shared drives hosted by third parties or public servers, the attack surface is significant. An attacker does not necessarily need physical access to the device; they only require network connectivity to serve a malicious NFS response. Successful exploitation could allow an adversary to bypass security controls such as sandboxing and code signing, gaining full control over the affected iOS, iPadOS, macOS, tvOS, visionOS, or watchOS device. This undermines the integrity of the entire system, potentially leading to data exfiltration, persistence mechanisms being installed, or complete compromise of user privacy and corporate secrets stored on the device.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-416, which defines use-after-free errors as a distinct category of memory safety violations. In terms of offensive security frameworks, this flaw facilitates techniques associated with MITRE ATT&CK tactic TA0005, specifically Defense Evasion through process injection or hooking via kernel exploitation. The ability to corrupt kernel memory enables attackers to establish rootkits that are difficult for standard endpoint detection and response tools to identify because they operate at a level below typical user-space monitoring agents.
Mitigation requires immediate adherence to the provided software updates. Apple has addressed this issue in iOS 26.7, iPadOS 26.7, iOS 27, iPadOS 27, macOS Golden Gate 27, macOS Sequoia 15.8, macOS Tahoe 26.7, tvOS 27, visionOS 27, and watchOS 27. Organizations should enforce automated update policies to ensure all endpoints are patched against this kernel-level vulnerability. Additionally, users should exercise caution when connecting to NFS shares from untrusted sources or public networks until the patch is applied. Implementing network segmentation and restricting access to internal file servers can further reduce exposure by limiting the ability of external malicious actors to interact with vulnerable devices over the NFS protocol.