CVE-2026-64081 in Linux
Summary
by MITRE • 07/19/2026
In the Linux kernel, the following vulnerability has been resolved:
firmware: arm_ffa: Validate framework notification message layout
Framework notifications carry an indirect message in the shared RX buffer. Validate the reported offset and size before using them, reject zero-length payloads, and ensure that any non-header payload starts at the UUID field rather than in the middle of the message header.
Use the validated offset and size values for both kmemdup() and the UUID parsing path so malformed firmware data cannot drive an out-of-bounds read or an oversized allocation.
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Analysis
by VulDB Data Team • 07/19/2026
The vulnerability resides within the linux kernel's firmware handling subsystem specifically in the arm_ffa framework which manages communication between secure and non-secure worlds on arm architectures. This framework processes notification messages that are transmitted through a shared receive buffer, creating a potential attack surface where malformed firmware data could be exploited to compromise system integrity. The flaw represents a classic input validation issue where untrusted data from firmware sources is processed without proper bounds checking, allowing for potentially malicious manipulation of memory access patterns.
The technical implementation of this vulnerability stems from inadequate validation of message layout parameters within the framework notification processing code. When firmware sends notification messages through the shared RX buffer, these messages contain indirect data that specifies both an offset and size for accessing the actual payload content. The kernel fails to validate these reported values before utilizing them in subsequent memory operations, creating opportunities for attackers to specify invalid offsets or sizes that could result in out-of-bounds memory access. This validation gap is particularly dangerous because it affects critical memory allocation functions where malformed data could trigger either oversized memory allocations or attempts to read beyond valid buffer boundaries.
The operational impact of this vulnerability extends beyond simple memory corruption scenarios and can potentially enable privilege escalation attacks within the secure world environment. When an attacker crafts malicious firmware notifications with crafted offset and size values, they could force the kernel to perform kmemdup() operations with invalid parameters, leading to either system crashes through memory allocation failures or more insidiously through controlled out-of-bounds reads that might leak sensitive information from kernel memory. The specific constraint requiring non-header payload to start at UUID field rather than within message header demonstrates the framework's understanding of message structure requirements, making this vulnerability particularly targeted toward manipulating these precise memory access patterns.
The mitigation strategy involves implementing comprehensive validation checks before any memory operations are performed on the reported offset and size values from firmware notifications. This includes rejecting zero-length payloads which would otherwise cause allocation failures or null pointer dereferences, ensuring that all payload processing begins at the correct UUID field location within the message structure, and using only validated parameters for both kernel memory duplication functions and UUID parsing operations. This approach aligns with common security best practices for input validation and follows principles outlined in CWE-129 which addresses insufficient validation of array index values. The solution also incorporates elements of defensive programming techniques that would be categorized under ATT&CK tactic T1068 which deals with exploit private vulnerabilities, as the fix prevents exploitation through malformed firmware data inputs.
This vulnerability highlights the critical importance of validating all inputs from potentially untrusted sources within kernel space operations, particularly when dealing with hardware abstraction layers and secure world communication frameworks. The ARM FFA (Fast Forward Messaging) framework represents a complex interface between different security domains where proper validation becomes essential to prevent attackers from leveraging memory layout assumptions to gain unauthorized access or execute arbitrary code in kernel mode. The fix demonstrates the principle of least privilege enforcement by ensuring that all firmware-provided parameters are validated before being used in operations that could affect system stability or security boundaries, particularly when these parameters control memory allocation and access patterns within kernel space.