CVE-2022-49584 is a vulnerability identified in the Linux kernel's ixgbe network driver, which handles Intel 10 Gigabit Ethernet adapters. The flaw arises when the number of SR-IOV (Single Root I/O Virtualization) Virtual Functions (VFs) is set to zero while the Physical Function (PF) driver is concurrently processing requests from the VF driver. Specifically, the vulnerability is due to a lack of proper locking mechanisms when disabling VFs, which can lead to a race condition. This race condition can cause the kernel to panic due to an invalid memory access, as evidenced by the kernel oops message and paging request failure detailed in the description. The panic occurs in the ixgbe_msg_task function, which is involved in VF mailbox communication. The vulnerability can be reproduced by repeatedly enabling and disabling VFs via the sysfs interface (writing to /sys/class/net/<devname>/device/sriov_numvfs), which triggers the race condition. The root cause is the absence of synchronization when disabling SR-IOV, allowing the PF driver to disable VFs while VF drivers are still communicating, leading to use-after-free or null pointer dereferences. This vulnerability affects Linux kernel versions containing the specified commit hash d773d1310625be3b040b436178ad59a0af8888f1. The issue has been addressed by adding locking to prevent disabling VFs during active VF driver processing, thereby preventing kernel panic. No known exploits are reported in the wild as of now, and no CVSS score has been assigned yet.

For European organizations, this vulnerability poses a significant risk to systems running Linux kernels with affected ixgbe drivers, particularly those using SR-IOV for network virtualization. SR-IOV is commonly employed in data centers, cloud environments, and virtualized infrastructures to improve network performance by allowing multiple virtual machines to share a single physical network interface. A kernel panic caused by this vulnerability results in a denial of service (DoS) condition, leading to system crashes and potential downtime. This can disrupt critical services, especially in environments relying on high availability and network virtualization, such as financial institutions, telecommunications providers, and cloud service operators. While the vulnerability does not directly enable privilege escalation or remote code execution, the induced DoS can be exploited by attackers with local access or by malicious scripts to degrade service availability. The impact on confidentiality and integrity is minimal; however, availability is severely affected. Given the widespread use of Linux in European enterprise and cloud infrastructures, the vulnerability could affect a broad range of organizations, particularly those using Intel 10GbE adapters with SR-IOV enabled. The lack of known exploits reduces immediate risk, but the ease of reproducing the issue via a simple script increases the likelihood of accidental or intentional triggering.

European organizations should take the following specific mitigation steps: 1) Immediately update Linux kernels to versions where the ixgbe driver includes the locking fix for SR-IOV VF disabling. Monitor vendor advisories and apply patches promptly. 2) If patching is not immediately feasible, temporarily disable SR-IOV on affected network interfaces to prevent triggering the vulnerability. This can be done by setting sriov_numvfs to zero and avoiding rapid toggling. 3) Implement strict access controls to limit who can modify SR-IOV settings, as local user or process access is required to exploit this vulnerability. 4) Monitor system logs for kernel panics or oops messages related to ixgbe to detect potential exploitation attempts or accidental triggers. 5) In virtualized environments, coordinate with hypervisor and network teams to ensure that SR-IOV configurations are stable and not subject to frequent changes that could trigger the race condition. 6) Conduct internal audits of network driver versions and SR-IOV usage to identify at-risk systems. 7) Develop incident response plans to quickly recover from kernel panics, including automated reboots and failover mechanisms to minimize downtime.