CVE-2024-21979 is an out-of-bounds write vulnerability classified under CWE-787 found in the AMD Radeon user mode driver component of AMD Software: Adrenalin Edition, specifically affecting DirectX 11 operations. This vulnerability arises when the driver processes a malformed shader, which can cause memory corruption by writing outside the intended buffer boundaries. Such memory corruption can lead to arbitrary code execution within the context of the user mode driver, potentially allowing an attacker to escalate privileges or execute malicious code. The attack vector requires an attacker to have local access with low privileges (AV:L) and the ability to supply a crafted shader to the driver. No user interaction is required, and the scope remains unchanged (S:U), meaning the impact is confined to the vulnerable component without affecting other system components. The CVSS v3.1 base score is 5.3, indicating medium severity, with impacts on confidentiality, integrity, and availability rated as low. No patches or exploits are currently publicly available, but the vulnerability is published and should be addressed promptly. The vulnerability is significant in environments where untrusted or malicious shaders can be introduced, such as gaming, professional graphics, or compute workloads using DirectX 11 on AMD GPUs.

For European organizations, this vulnerability poses a moderate risk primarily in environments where AMD GPUs running the affected driver versions are used, especially in sectors relying on graphics-intensive applications like gaming, media production, and scientific computing. Successful exploitation could lead to arbitrary code execution, potentially allowing attackers to compromise system integrity, steal sensitive information, or disrupt availability. However, the requirement for local low-privilege access limits remote exploitation risks. Organizations with shared workstations or environments where untrusted users can run custom shaders are at higher risk. The vulnerability could be leveraged as part of a multi-stage attack to escalate privileges or move laterally within networks. Confidentiality, integrity, and availability impacts are all possible but limited in scope. The absence of known exploits reduces immediate risk but does not eliminate the need for proactive mitigation.

European organizations should implement the following specific mitigations: 1) Monitor AMD’s official channels for patches addressing CVE-2024-21979 and apply updates promptly once available. 2) Restrict the execution of untrusted or unsigned shaders, especially in multi-user or shared environments, by enforcing strict application whitelisting and code signing policies. 3) Limit local user privileges to the minimum necessary to reduce the likelihood of low-privilege attackers exploiting the vulnerability. 4) Employ endpoint detection and response (EDR) solutions to monitor for unusual behavior related to GPU driver processes. 5) Educate users about the risks of running untrusted software or shaders, particularly in environments where DirectX 11 is heavily used. 6) Consider isolating critical systems that use AMD GPUs from untrusted networks or users to reduce exposure. 7) Regularly audit and update GPU drivers to the latest versions to benefit from security improvements.