CVE-2024-26646 is a vulnerability identified in the Linux kernel related to the handling of the Hardware Feedback Interface (HFI) buffer during system suspend, hibernation, and resume cycles. The Linux kernel allocates a memory buffer at boot time and provides its location to the hardware, which uses this buffer to update the HFI table. This buffer remains constant throughout runtime under normal operation. However, when the system resumes from hibernation, the restore kernel allocates a second memory buffer and reprograms the HFI hardware with the new buffer location. The location of this second buffer may differ from the original image kernel’s buffer. When control is transferred back to the image kernel, the original HFI buffer becomes invalid, but the hardware may continue to write to the now-invalid buffer from the restore kernel. This discrepancy can lead to memory corruption. Additionally, during a "deep" suspend, the hardware may lose track of the buffer address, which can also cause memory corruption. To mitigate this, the Linux kernel developers introduced syscore callbacks that disable the HFI interface when preparing for suspend or hibernation and re-enable it upon resume. These callbacks run on the boot CPU and ensure that HFI is only disabled during deep suspend and hibernation states, preventing the hardware from writing to invalid memory buffers. This vulnerability arises from improper synchronization between hardware buffer usage and kernel memory allocation during power state transitions, potentially leading to memory corruption and system instability.

For European organizations relying on Linux-based systems, especially those using Intel hardware with HFI support, this vulnerability poses a risk of system instability or crashes following suspend or hibernation cycles. Memory corruption could lead to unpredictable behavior, including potential data loss, system downtime, or denial of service. Organizations operating critical infrastructure, data centers, or cloud services that utilize Linux servers with affected kernel versions may experience disruptions. Although there is no evidence of active exploitation in the wild, the vulnerability could be leveraged by attackers with local access or through crafted scenarios involving power state transitions to cause system failures or escalate privileges indirectly by destabilizing kernel memory management. The impact is particularly relevant for sectors with high availability requirements such as finance, healthcare, and manufacturing within Europe. Additionally, embedded Linux devices and IoT systems that utilize suspend or hibernation features could be affected, potentially impacting operational technology environments.

European organizations should prioritize updating their Linux kernels to versions that include the patch addressing CVE-2024-26646. Since the vulnerability is related to kernel-level memory management during suspend and hibernation, kernel updates from trusted Linux distributions should be applied promptly. For environments where immediate patching is not feasible, organizations can consider disabling suspend and hibernation features temporarily to avoid triggering the vulnerable code paths. System administrators should audit and monitor systems for unexpected crashes or memory corruption symptoms following resume operations. Additionally, organizations should ensure that their hardware firmware and drivers are up to date, as coordinated updates may be necessary for full mitigation. Testing updates in staging environments before deployment is recommended to verify stability. For embedded or specialized Linux deployments, vendors should be contacted to confirm patch availability or workarounds. Finally, implementing strict access controls to limit local user privileges can reduce the risk of exploitation attempts that require local access.