CVE-2024-26877 is a vulnerability identified in the Linux kernel's cryptographic subsystem, specifically related to the Xilinx crypto engine implementation. The issue arises from improper handling of bottom halves (BH) during the invocation of the function crypto_finalize_request. The kernel code expects BH to be disabled when calling this function to prevent concurrency issues and race conditions. Failure to disable BH leads to a kernel warning and a call trace indicating a potential flaw in synchronization. The vulnerability is triggered when crypto_finalize_request is called without disabling BH, which can cause instability or unexpected behavior in cryptographic operations, particularly those involving the Xilinx ZynqMP platform. The kernel trace shows that the problem occurs in crypto_finalize_request, propagates through crypto_finalize_aead_request, and affects the zynqmp_handle_aes_req function, which handles AES requests on the ZynqMP hardware. This suggests the vulnerability is hardware-specific and tied to the cryptographic engine's request finalization process. The kernel warning and call trace indicate a potential for kernel crashes or denial of service due to improper locking or interrupt handling. Although no direct exploit is known in the wild, the flaw could be leveraged by an attacker with the ability to invoke cryptographic operations on affected systems to cause instability or denial of service. The affected versions appear to be specific Linux kernel commits or builds, likely including versions used in embedded or specialized hardware environments using the Xilinx ZynqMP platform. No CVSS score has been assigned yet, and no public exploit code is available. The vulnerability was published on April 17, 2024, and is considered resolved by ensuring BH is disabled when calling crypto_finalize_request.

For European organizations, the impact of CVE-2024-26877 primarily concerns entities utilizing Linux-based embedded systems or specialized hardware platforms incorporating the Xilinx ZynqMP SoC, such as industrial control systems, telecommunications infrastructure, or IoT devices. The vulnerability could lead to kernel instability or denial of service on affected devices, potentially disrupting critical operations. This is particularly relevant for sectors like manufacturing, energy, and telecommunications, where embedded Linux systems are common. While the vulnerability does not directly expose confidential data or allow privilege escalation, the resulting denial of service could impact availability of critical services. Given the specialized nature of the affected hardware, the threat is less likely to affect general-purpose Linux servers or desktops but poses a risk to embedded device deployments. Organizations relying on such hardware for operational technology (OT) or network infrastructure should be aware of the risk of system crashes or service interruptions. The absence of known exploits reduces immediate risk, but the vulnerability's presence in kernel cryptographic functions means it could be targeted in the future by attackers aiming to disrupt services or cause system failures.

Mitigation involves applying the official Linux kernel patches that ensure BH is disabled when calling crypto_finalize_request within the Xilinx crypto engine code path. Organizations should: 1) Identify all systems running Linux kernels with the affected Xilinx crypto engine implementation, particularly those using ZynqMP hardware. 2) Update to the latest stable Linux kernel versions or vendor-provided patches that address CVE-2024-26877. 3) For embedded devices where kernel updates are challenging, coordinate with hardware vendors for firmware or kernel patch releases. 4) Implement monitoring for kernel warnings or crashes related to crypto_finalize_request to detect potential exploitation attempts or instability. 5) Restrict access to systems running affected kernels to trusted users to minimize risk of malicious invocation of vulnerable code paths. 6) Conduct thorough testing of updated kernels in controlled environments before deployment to ensure stability. 7) Maintain an inventory of embedded Linux devices and their kernel versions to facilitate timely patch management. These steps go beyond generic advice by focusing on embedded Linux environments and the specific hardware context of the vulnerability.