CVE-2026-28931 in iOS
Summary
by MITRE • 07/27/2026
A buffer overflow was addressed with improved bounds checking. This issue is fixed in iOS 26.6 and iPadOS 26.6, macOS Tahoe 26.6, tvOS 26.6, watchOS 26.6. Connecting to a malicious NFS server may lead to kernel memory corruption.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 07/27/2026
This vulnerability represents a classic buffer overflow condition that was remediated through enhanced bounds checking mechanisms within Apple's operating system kernels. The flaw existed in the Network File System implementation across multiple Apple platforms including iOS, iPadOS, macOS Tahoe, tvOS, and watchOS versions prior to 26.6. The vulnerability stems from inadequate input validation when processing data structures from remote NFS servers, creating a potential pathway for malicious actors to exploit kernel memory management functions.
The technical execution of this vulnerability occurs when a device connects to a specially crafted malicious NFS server that sends malformed data packets designed to exceed allocated buffer boundaries. This type of flaw maps directly to CWE-121 which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The kernel memory corruption aspect indicates that the overflow extends beyond user-space application boundaries into critical system memory regions, potentially enabling privilege escalation and system compromise.
Operationally this vulnerability presents a significant risk for organizations relying on NFS connectivity, as it requires no local user interaction or device compromise to exploit. An attacker merely needs to establish a connection to a malicious NFS server to trigger the buffer overflow condition. The impact extends beyond simple denial of service to potential full system compromise, as demonstrated by similar kernel-level buffer overflow exploits that have been weaponized in advanced persistent threat campaigns. This aligns with ATT&CK technique T1068 which covers local privilege escalation through kernel vulnerabilities.
The remediation implemented in Apple's 26.6 updates focuses on strengthening input validation and bounds checking mechanisms within the NFS client implementation. These fixes typically involve adding explicit size checks before memory allocation operations, implementing proper buffer boundary verification, and ensuring that all data received from remote sources is strictly validated against expected parameters. Organizations should prioritize immediate deployment of these security updates across all affected platforms to eliminate the risk of exploitation.
Security teams should monitor for potential exploitation attempts targeting this vulnerability through network traffic analysis, particularly looking for unusual NFS connection patterns or malformed data transfers. The vulnerability's presence in multiple Apple operating systems suggests a coordinated attack surface that requires comprehensive patch management strategies. Given the kernel-level nature of the flaw and its potential for privilege escalation, organizations should consider implementing additional network segmentation controls to limit access to NFS services and reduce the attack surface for potential exploitation attempts.