CVE-2024-46837 is a vulnerability identified in the Linux kernel's Direct Rendering Manager (DRM) subsystem, specifically within the Panthor driver component used by the Panfrost GPU driver stack. The issue arises from insufficient permission checks when creating groups with high scheduling priorities. Originally, any user was able to create a high priority group without restrictions, which could lead to denial of service (DoS) conditions by allowing unprivileged users to monopolize CPU scheduling resources. The vulnerability stems from the panthor_group_create ioctl interface, which did not enforce adequate permission validation for priority levels above PANTHOR_GROUP_PRIORITY_MEDIUM. The fix restricts the ability to assign priorities higher than medium to only the DRM master or users possessing the CAP_SYS_NICE capability, which is a privileged capability allowing modification of process scheduling priorities. Since the only known user of this interface is Mesa's Panfrost driver, which hardcodes the priority to medium, this change is expected to be safe and not break legitimate functionality. The checks are now performed at the ioctl level, ensuring that unauthorized users cannot escalate priority levels and cause resource starvation. No known exploits are currently reported in the wild, and the vulnerability was published on September 27, 2024. This vulnerability primarily affects Linux kernel versions containing the specified commit hashes prior to the patch. The root cause is a lack of permission enforcement on scheduling priority assignment in a GPU driver context, which could be exploited to degrade system availability by causing CPU resource exhaustion or starvation of critical processes.

For European organizations, this vulnerability poses a risk primarily in environments running Linux systems with the affected kernel versions and utilizing the Panfrost GPU driver, which is common in ARM-based devices and some embedded systems. The potential impact is a denial of service condition where unprivileged users could degrade system performance or cause critical services to become unresponsive by creating high priority groups that monopolize CPU scheduling. This could affect servers, workstations, or embedded devices used in industrial control, telecommunications, or cloud infrastructure. Organizations relying on Linux-based infrastructure with GPU acceleration or graphical workloads could see availability disruptions. Although the vulnerability does not directly compromise confidentiality or integrity, the availability impact could interrupt business operations, especially in sectors requiring high uptime such as finance, healthcare, and critical infrastructure. The absence of known exploits reduces immediate risk, but the ease of exploitation (no authentication required beyond local user access) means insider threats or compromised accounts could leverage this vulnerability. European organizations with multi-user Linux environments or shared hosting platforms are particularly at risk if they do not restrict user capabilities properly.

To mitigate this vulnerability, European organizations should: 1) Apply the latest Linux kernel patches that include the fix restricting high priority group creation to privileged users only. 2) Audit and restrict CAP_SYS_NICE capability assignments to trusted users only, minimizing the number of users who can manipulate scheduling priorities. 3) Implement strict user privilege separation and avoid granting unnecessary permissions to unprivileged users, especially on systems with GPU acceleration. 4) Monitor system logs and ioctl calls related to DRM and Panfrost driver activity for unusual priority escalation attempts. 5) For environments where patching is delayed, consider disabling or restricting access to the Panfrost driver if not required. 6) Employ resource control mechanisms such as cgroups or systemd slices to limit CPU resource usage per user or group, mitigating potential DoS impact. 7) Educate system administrators about this vulnerability and ensure proper kernel version management and vulnerability scanning are part of routine security operations.