CVE-2024-50035 is a vulnerability identified in the Linux kernel's Point-to-Point Protocol (PPP) implementation, specifically within the asynchronous PPP encoding function ppp_async_encode(). The issue arises when the function pppoe_sendmsg() is called with a zero size, which subsequently leads to ppp_async_encode() being invoked with an empty socket buffer (skb). This sequence results in the use of uninitialized memory values within the ppp_async_encode() and ppp_async_push() functions, as detected by Kernel Memory Sanitizer (KMSAN). The root cause is an illegal memory access due to uninitialized data usage, which can cause kernel instability or crashes. The vulnerability was reported by syzbot, an automated kernel bug-finding tool, and affects Linux kernel versions including the 6.12.0-rc1 release candidate. The detailed kernel call stack shows the flow from pppoe_sendmsg() through various PPP-related functions, highlighting the memory allocation and skb handling paths where the uninitialized memory is introduced. Although no CVSS score has been assigned yet, the vulnerability is significant because it involves kernel-level memory corruption, which can potentially be exploited to cause denial of service or escalate privileges if combined with other vulnerabilities. However, exploitation requires triggering specific PPPoE (PPP over Ethernet) message sending with crafted parameters, which may limit the attack surface to systems actively using PPPoE networking.

For European organizations, the impact of CVE-2024-50035 depends largely on the deployment of Linux systems utilizing PPPoE connections. PPPoE is commonly used in broadband internet access, especially in DSL environments, which remain prevalent in parts of Europe. A successful exploitation could lead to kernel crashes causing denial of service, potentially disrupting network connectivity and critical services. In environments where PPPoE is used for VPNs or other secure tunnels, this vulnerability could undermine network reliability. Although there is no evidence of active exploitation, the kernel memory corruption could be leveraged in multi-stage attacks to gain elevated privileges or execute arbitrary code, posing a risk to confidentiality and integrity. European sectors such as telecommunications, ISPs, and enterprises relying on Linux-based network infrastructure are particularly at risk. The vulnerability could also affect embedded Linux devices used in network equipment, increasing the scope of impact. Given the critical role of Linux in European IT infrastructure, unpatched systems could face operational disruptions and increased attack surface.

To mitigate CVE-2024-50035, European organizations should prioritize updating Linux kernels to versions where this vulnerability is patched. Since the issue is in the PPP asynchronous encoding code, disabling or limiting the use of PPPoE interfaces where feasible can reduce exposure. Network administrators should audit their environments to identify systems using PPPoE and assess the necessity of this protocol. Employing kernel hardening techniques such as Kernel Address Sanitizer (KASAN) and Kernel Memory Sanitizer (KMSAN) during testing phases can help detect similar issues proactively. Additionally, implementing strict network segmentation and firewall rules to restrict PPPoE traffic to trusted sources can limit exploitation opportunities. Monitoring kernel logs for unusual PPPoE activity and crashes can provide early detection of attempted exploitation. For embedded devices or appliances running vulnerable Linux kernels, vendors should be contacted for firmware updates or mitigations. Finally, organizations should maintain robust incident response plans to quickly address any kernel-level compromises.