CVE-2022-49574 is a concurrency-related vulnerability found in the Linux kernel's TCP networking stack. Specifically, the issue arises around the sysctl_tcp_recovery variable, which is used to control TCP recovery behavior. The vulnerability occurs because sysctl_tcp_recovery can be read concurrently while it is being modified, leading to potential data races. Data races happen when multiple threads or processors access and manipulate shared data simultaneously without proper synchronization, causing inconsistent or corrupted data states. In this case, the lack of atomicity or proper memory barriers when reading sysctl_tcp_recovery means that the value could be partially updated or inconsistent during concurrent access. The fix involves adding the READ_ONCE() macro to the readers of sysctl_tcp_recovery. READ_ONCE() is a Linux kernel macro that ensures the variable is read atomically and prevents compiler or CPU reordering optimizations that could cause inconsistent reads. By enforcing atomic reads, the race condition is mitigated, ensuring that any thread reading sysctl_tcp_recovery obtains a consistent and valid value. This vulnerability is rooted in kernel-level concurrency control and affects the TCP subsystem, which is critical for network communication. Although the description does not specify direct exploit scenarios or known exploits in the wild, data races in kernel code can potentially lead to undefined behavior, including kernel crashes (denial of service), information leakage, or even privilege escalation if exploited in combination with other vulnerabilities. The affected versions are identified by a specific commit hash, indicating that this vulnerability is present in certain Linux kernel versions prior to the patch. No CVSS score is provided, and no known exploits have been reported as of the publication date (February 26, 2025).

For European organizations, this vulnerability could impact any systems running affected Linux kernel versions, particularly those that rely heavily on TCP networking for critical services such as web servers, database servers, cloud infrastructure, and network appliances. The primary risk is potential system instability or denial of service due to kernel crashes triggered by race conditions. While direct exploitation to gain unauthorized access or escalate privileges is not explicitly documented, the vulnerability could be leveraged as part of a multi-stage attack chain. Organizations operating critical infrastructure, financial services, telecommunications, and cloud service providers in Europe could face disruptions if attackers find ways to exploit this race condition. Additionally, the vulnerability could affect embedded Linux devices used in industrial control systems or IoT deployments prevalent in European manufacturing and energy sectors. Given the widespread use of Linux in enterprise and cloud environments, the impact could be broad but is likely limited to service availability and stability rather than direct data breaches or confidentiality loss.

1. Immediate application of the official Linux kernel patch that adds READ_ONCE() to sysctl_tcp_recovery readers is essential. Organizations should monitor Linux kernel updates and apply security patches promptly. 2. For environments where kernel patching is not immediately feasible, consider isolating vulnerable systems from untrusted networks to reduce exposure. 3. Employ kernel live patching technologies (such as kpatch or ksplice) where supported to minimize downtime while applying fixes. 4. Conduct thorough testing of updated kernels in staging environments to ensure stability before production deployment. 5. Monitor system logs and kernel messages for unusual TCP stack behavior or crashes that could indicate exploitation attempts. 6. Maintain a robust incident response plan to quickly address any denial of service or instability issues arising from this vulnerability. 7. For embedded or specialized Linux devices, coordinate with vendors to obtain patched firmware or kernel versions. 8. Implement network segmentation and strict access controls to limit the attack surface of vulnerable systems.