CVE-2024-41090 is a vulnerability identified in the Linux kernel's tap network interface implementation. Specifically, the flaw arises from missing verification for short Ethernet frames in the tap_get_user_xdp() code path. The vulnerability occurs because the code fails to validate the frame length before processing, which can lead to corrupted socket buffers (skbs) being passed down the network stack. The tap_get_user_xdp() function assumes the frame size is at least the size of an Ethernet header (ETH_HLEN), but without proper length checks, it may operate on frames shorter than this minimum size. This can cause out-of-bounds memory access or inconsistent skb metadata, potentially confusing lower network layers or causing memory corruption. The alternative code path, tap_get_user(), already includes a check to drop frames shorter than the Ethernet header size, but this was missing in tap_get_user_xdp(). The vulnerability was addressed by adding the missing verification to drop any frame shorter than the Ethernet header size, aligning the behavior of tap_get_user_xdp() with tap_get_user(). This flaw could be exploited by an attacker capable of injecting crafted short frames into the tap interface, potentially leading to kernel memory corruption or instability. However, no known exploits are currently reported in the wild. The vulnerability affects Linux kernel versions identified by the commit hash 0efac27791ee068075d80f07c55a229b1335ce12 and possibly others in the same timeframe. Since the Linux kernel is widely used across servers, desktops, and embedded devices, this vulnerability has broad potential impact. The issue is technical and low-level, requiring attacker access to the tap interface and the ability to send malformed frames, which may limit exploitation scenarios but still poses a risk to systems using tap interfaces for networking, such as virtualized environments and container platforms.

For European organizations, the impact of CVE-2024-41090 could be significant in environments where Linux is used extensively, especially in data centers, cloud infrastructure, and virtualized or containerized deployments that rely on tap interfaces for network bridging. Exploitation could lead to kernel memory corruption, causing system crashes, denial of service, or potentially privilege escalation if combined with other vulnerabilities. This could disrupt critical services, including web hosting, financial systems, and industrial control systems. Given the widespread adoption of Linux in European enterprises and public sector organizations, the vulnerability could affect a broad range of industries including finance, telecommunications, government, and manufacturing. The risk is heightened in multi-tenant cloud environments where an attacker might exploit the vulnerability from a compromised virtual machine or container to affect the host or other tenants. Although no exploits are known in the wild, the vulnerability’s presence in a core kernel component means that once weaponized, it could be used for targeted attacks or lateral movement within networks. The impact on confidentiality is moderate to high if kernel memory corruption can be leveraged for privilege escalation. Integrity and availability impacts are also significant due to potential system instability or crashes.

European organizations should prioritize patching Linux kernel versions affected by CVE-2024-41090 as soon as updates become available from their Linux distribution vendors. Specifically, ensure that all systems using tap interfaces, including virtualized hosts, container platforms, and network appliances, are updated. Network administrators should audit the use of tap interfaces and restrict access to trusted users and processes to minimize the risk of malicious frame injection. Employ network segmentation and strict firewall rules to limit exposure of tap interfaces to untrusted networks or users. Monitoring kernel logs and network traffic for anomalies related to short or malformed Ethernet frames can help detect attempted exploitation. Organizations should also review their virtualization and container orchestration configurations to ensure that tap interfaces are not unnecessarily exposed. In environments where immediate patching is not feasible, consider disabling or restricting tap interface usage temporarily. Finally, maintain robust incident response plans to quickly address any signs of exploitation or system instability related to this vulnerability.