CVE-2024-26584 addresses a vulnerability in the Linux kernel's TLS (Transport Layer Security) implementation related to the handling of cryptographic requests in the kernel's crypto API. Specifically, the issue arises from how the kernel manages backlogging of asynchronous cryptographic operations, particularly when the cryptographic device queue (cryptd queue) for AES-NI (Advanced Encryption Standard New Instructions) is full. Under these conditions, the crypto API may return an -EBUSY error instead of the expected -EINPROGRESS error, which can cause the asynchronous callback to be invoked twice: first with an error indicating the operation is in progress (-EINPROGRESS), and then with a success indication (err == 0). This behavior can lead to confusion in error handling paths and potentially cause incorrect processing of cryptographic operations. The patch resolves this by converting the -EBUSY error back to -EINPROGRESS using new helper functions (tls_*crypt_async_wait()), thereby maintaining consistent error handling without requiring extensive changes to existing code. This fix ensures that cryptographic requests are properly queued and processed even under high load, preventing potential race conditions or mishandling of TLS encryption/decryption operations within the kernel. The vulnerability does not appear to have known exploits in the wild and affects specific Linux kernel versions identified by commit hashes. No CVSS score has been assigned yet, and the vulnerability is primarily related to the internal kernel cryptographic subsystem's robustness and correctness rather than a direct remote code execution or privilege escalation vector.

For European organizations, the impact of CVE-2024-26584 is primarily related to the reliability and correctness of TLS cryptographic operations within Linux-based systems. Since Linux is widely used in servers, cloud infrastructure, and networking equipment across Europe, any instability or incorrect handling in the kernel's TLS implementation could lead to degraded service availability or potential data integrity issues during encrypted communications. While this vulnerability does not directly enable remote code execution or privilege escalation, mishandling of cryptographic operations could theoretically cause TLS sessions to fail or behave unpredictably, impacting secure communications. This is particularly critical for sectors relying heavily on secure data transmission such as finance, healthcare, telecommunications, and government services. However, given the nature of the vulnerability and the absence of known exploits, the immediate risk is moderate. Organizations running Linux kernels with the affected versions should prioritize patching to ensure cryptographic operations remain reliable and to prevent any indirect impacts on confidentiality or availability of encrypted data streams.

European organizations should take the following specific mitigation steps: 1) Identify Linux systems running affected kernel versions by checking kernel commit hashes or Linux distribution security advisories. 2) Apply the official Linux kernel patches that address CVE-2024-26584 as soon as they become available from trusted sources or Linux distribution vendors. 3) For environments using custom or embedded Linux kernels, coordinate with vendors or internal development teams to integrate the patch promptly. 4) Monitor cryptographic subsystem logs and TLS-related kernel messages for anomalies that might indicate issues with cryptographic request handling. 5) Implement robust testing of TLS-dependent applications and services after patching to verify stability and correct operation under load conditions. 6) Maintain up-to-date kernel versions and subscribe to Linux security mailing lists or advisories to stay informed about related vulnerabilities. 7) Consider limiting the cryptd queue length or tuning cryptographic subsystem parameters cautiously to avoid triggering backlog conditions until patches are applied. These targeted actions go beyond generic advice by focusing on kernel-level patching, monitoring, and configuration tuning specific to the cryptographic subsystem involved.