CVE-2022-48671 is a medium-severity vulnerability in the Linux kernel related to the control groups (cgroup) subsystem, specifically involving improper locking in the function cgroup_attach_task_all(). The vulnerability arises because the cpus_read_lock() was missing in cgroup_attach_task_all(), which leads to a potential deadlock or race condition when attaching tasks to cgroups. The issue was identified by syzbot, which detected a percpu_rwsem_assert_held(&cpu_hotplug_lock) warning at cpuset_attach(). The root cause is that the commit fixing a previous deadlock between threadgroup_rwsem and cpus_read_lock() missed that cpuset_attach() is also called from cgroup_attach_task_all(), requiring the cpus_read_lock() to be held. Without this lock, concurrent operations on CPU sets and cgroup task attachments can cause inconsistent states or kernel warnings, potentially leading to denial of service (DoS) conditions due to kernel hangs or crashes. The vulnerability affects multiple Linux kernel versions identified by specific commit hashes. The CVSS 3.1 score is 5.5 (medium), with attack vector local, low attack complexity, low privileges required, no user interaction, unchanged scope, no confidentiality or integrity impact, but high impact on availability. No known exploits are reported in the wild yet. The weakness corresponds to CWE-667 (Improper Locking), indicating synchronization issues in kernel code that can cause deadlocks or race conditions. This vulnerability is technical and subtle, requiring local access and some privileges to trigger, but it can disrupt system availability by causing kernel instability during cgroup task management operations.

For European organizations, the impact of CVE-2022-48671 primarily concerns systems running vulnerable Linux kernel versions, especially servers and infrastructure relying on cgroups for resource management and container orchestration (e.g., Kubernetes). A successful exploitation could cause kernel hangs or crashes, leading to denial of service on critical systems. This can disrupt business operations, cloud services, and containerized workloads. Given the widespread use of Linux in European data centers, cloud providers, and enterprises, the availability impact could affect service continuity and SLAs. However, since the vulnerability requires local access and some privileges, remote exploitation is unlikely, limiting the attack surface to insiders or compromised accounts. The absence of confidentiality or integrity impact reduces risks of data breaches or unauthorized modifications. Still, availability disruptions in critical infrastructure sectors such as finance, healthcare, and government could have significant operational and reputational consequences. Organizations using container platforms or cgroup-based resource controls should prioritize patching to prevent potential DoS conditions.

1. Apply the official Linux kernel patches that address CVE-2022-48671 as soon as they become available for your distribution or kernel version. 2. For organizations using container orchestration platforms like Kubernetes, ensure that the underlying nodes run updated kernels with the fix to prevent cgroup-related deadlocks. 3. Restrict local access and privilege escalation paths to minimize the risk of an attacker gaining the necessary privileges to exploit this vulnerability. 4. Monitor kernel logs for warnings related to percpu_rwsem_assert_held or cpuset_attach() anomalies that may indicate attempts to trigger the issue. 5. Employ kernel live patching solutions where possible to reduce downtime when applying fixes. 6. Conduct regular audits of user privileges and access controls on Linux hosts to limit exposure. 7. For critical systems, implement redundancy and failover mechanisms to mitigate potential availability disruptions caused by kernel instability. 8. Engage with Linux distribution vendors and subscribe to security advisories to stay informed about patch releases and related vulnerabilities.