CVE-2024-57902 is a vulnerability identified in the Linux kernel, specifically within the af_packet subsystem that handles packet sockets. The issue arises from improper handling in the vlan_get_tci() function when processing MSG_PEEK socket messages. The original implementation neglected the MSG_PEEK case, which can lead to a kernel crash due to a kernel BUG triggered by skb (socket buffer) manipulation errors. The vulnerability was discovered by syzbot, an automated kernel fuzzer, which detected a panic caused by invalid skb state during concurrent access. The root cause is that vlan_get_tci() touched the skb data structure in a way that was not safe for concurrent CPU access, leading to race conditions and memory corruption. The fix involved reworking vlan_get_tci() to avoid modifying the skb at all and adding a const qualifier to the skb argument to enforce read-only access. This correction ensures thread-safe access to skb data and prevents kernel panics triggered by crafted MSG_PEEK packets on AF_PACKET sockets. The vulnerability affects multiple Linux kernel versions prior to the patch and can be triggered by local processes that have the ability to open AF_PACKET sockets and send crafted messages. The crash results in a denial of service (DoS) by causing the kernel to panic and reboot or halt, impacting system availability. There is no indication that this vulnerability allows privilege escalation or arbitrary code execution. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, the primary impact of CVE-2024-57902 is a potential denial of service on Linux-based systems that utilize AF_PACKET sockets, commonly found in network appliances, servers, and devices performing advanced packet processing or network monitoring. Systems running vulnerable kernel versions may experience kernel panics and reboots when exposed to crafted MSG_PEEK packets, which could be exploited by local users or malicious software with socket access. This could disrupt critical services, especially in sectors relying heavily on Linux infrastructure such as finance, telecommunications, government, and industrial control systems. Although the vulnerability does not directly lead to data breaches or privilege escalation, the resulting downtime and instability could cause operational disruptions, loss of availability, and increased recovery costs. Additionally, denial of service in network devices could degrade network performance or interrupt connectivity, impacting business continuity. Organizations with multi-tenant environments or cloud deployments using affected Linux kernels should be particularly vigilant, as attackers might leverage this flaw to disrupt shared infrastructure.

To mitigate CVE-2024-57902, organizations should promptly apply the official Linux kernel patches that address the vlan_get_tci() MSG_PEEK handling issue. If immediate patching is not feasible, consider the following specific measures: 1) Restrict access to AF_PACKET sockets by limiting CAP_NET_RAW capability to trusted users and processes only, reducing the attack surface. 2) Employ kernel lockdown features or mandatory access controls (e.g., SELinux, AppArmor) to prevent unauthorized socket operations. 3) Monitor kernel logs for signs of skb_under_panic or related kernel BUG messages indicative of exploitation attempts. 4) In environments using containerization or virtualization, isolate workloads to minimize the impact of potential kernel crashes. 5) Regularly update kernel versions and subscribe to Linux security advisories to stay informed of patches and related vulnerabilities. 6) Conduct internal audits of network-facing systems to identify and remediate vulnerable kernel versions. These targeted steps go beyond generic advice by focusing on controlling socket access and monitoring for specific kernel panic indicators related to this vulnerability.