CVE-2024-47658 is a vulnerability identified in the Linux kernel specifically within the cryptographic subsystem for the STM32 platform (crypto: stm32/cryp). The issue arises during the finalize operation of cryptographic processing when executed in interrupt context. The vulnerability manifests as a spinlock recursion warning caused by improper handling of bottom halves (BH) during the finalize call. In Linux kernel programming, bottom halves represent deferred work that must be disabled to prevent concurrency issues during critical sections. The finalize operation in this case is called without disabling BH, leading to potential recursive locking of spinlocks. This can cause kernel warnings and may lead to deadlocks or system instability. The vulnerability is rooted in kernel synchronization mechanisms and interrupt handling, which are critical for maintaining kernel integrity and performance. Although no known exploits are currently reported in the wild, the flaw could be triggered by crafted kernel operations or malicious code running with sufficient privileges to invoke the affected cryptographic finalize function. The affected versions are identified by specific commit hashes, indicating the vulnerability is present in certain Linux kernel builds prior to the patch. The issue was reserved on 2024-09-30 and published on 2024-10-09, with no CVSS score assigned yet. The fix involves ensuring BH is disabled during the finalize call to prevent spinlock recursion warnings and maintain proper kernel synchronization.

For European organizations, the impact of CVE-2024-47658 primarily concerns systems running Linux kernels with the affected STM32 cryptographic module, which is common in embedded devices and IoT platforms. Organizations relying on Linux-based embedded systems for industrial control, telecommunications, or critical infrastructure could face system instability or kernel panics if the vulnerability is triggered. While the vulnerability does not directly lead to privilege escalation or data leakage, the potential for kernel deadlocks or crashes can disrupt services, leading to availability issues. This is particularly significant for sectors such as manufacturing, energy, and transportation, where embedded Linux devices are prevalent. Additionally, the cryptographic nature of the module suggests that secure communications or data protection functions could be impaired, indirectly affecting confidentiality and integrity if systems become unreliable or require emergency reboots. Given the absence of known exploits, the immediate risk is moderate; however, the vulnerability should be addressed promptly to prevent future exploitation or accidental system failures.

To mitigate CVE-2024-47658, European organizations should: 1) Apply the latest Linux kernel patches that address this vulnerability, ensuring the finalize operation disables bottom halves as required. 2) Identify and inventory all embedded and IoT devices running affected Linux kernel versions, particularly those using STM32 cryptographic modules. 3) For devices where patching is not immediately feasible, consider isolating them from critical networks or limiting their exposure to untrusted inputs to reduce risk. 4) Monitor kernel logs for spinlock recursion warnings or related kernel messages that may indicate attempts to trigger the vulnerability. 5) Collaborate with device vendors and maintainers to ensure firmware updates incorporate the fix. 6) Implement robust incident response plans for embedded device failures to minimize downtime. These steps go beyond generic advice by focusing on embedded Linux environments and the specific cryptographic module affected.