CVE-2021-47046 is a vulnerability identified in the Linux kernel specifically within the AMD GPU driver subsystem, related to the handling of HDCP (High-bandwidth Digital Content Protection) messages over HDMI. The flaw is an off-by-one read overflow in the function hdmi_14_process_transaction(), caused by the hdcp_i2c_offsets[] array lacking an entry for the HDCP_MESSAGE_ID_WRITE_CONTENT_STREAM_TYPE. This omission leads to an out-of-bounds read when processing certain HDCP messages, potentially causing memory corruption or information disclosure. The fix involved adding the missing array entry and marking several arrays with HDCP_MESSAGE_ID_MAX entries to future-proof the code. The vulnerability affects Linux kernel versions identified by the commit hash 4c283fdac08abf3211533f70623c90a34f41d08d, indicating a specific patch version. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The vulnerability is rooted in a kernel driver handling DRM (Direct Rendering Manager) for AMD GPUs, which is critical for graphics output and content protection mechanisms on Linux systems.

For European organizations, the impact of this vulnerability depends largely on the deployment of Linux systems with AMD GPUs that utilize HDCP for protected content transmission, such as media companies, broadcasters, or enterprises using Linux workstations with AMD graphics. Exploitation could lead to memory corruption or information leakage, potentially allowing local attackers or malicious processes to gain unauthorized access to sensitive data or cause system instability. While remote exploitation is unlikely without local access, the vulnerability could be leveraged in multi-user environments or containerized setups where privilege escalation or data leakage between users is a concern. The absence of known exploits reduces immediate risk, but the vulnerability could be targeted in the future, especially in sectors relying on secure media streaming or DRM enforcement. Disruption or compromise of graphics drivers could also affect availability of critical systems relying on Linux graphical interfaces.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2021-47046. Specifically, applying the commit identified by hash 4c283fdac08abf3211533f70623c90a34f41d08d or later is essential. Organizations should audit their systems to identify AMD GPU usage and verify kernel versions. For environments where immediate patching is not feasible, restricting access to systems with AMD GPUs and limiting user privileges can reduce exploitation risk. Monitoring system logs for unusual behavior related to DRM or GPU drivers may help detect attempted exploitation. Additionally, organizations should ensure that containerized or virtualized environments do not expose the vulnerable driver interfaces to untrusted users. Coordination with Linux distribution vendors for timely security updates and testing patches in staging environments before production deployment is recommended.