CVE-2025-38362: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-38362 is a NULL pointer dereference vulnerability in the Linux kernel's AMD display driver (drm/amd/display) affecting the HDCP (High-bandwidth Digital Content Protection) subsystem. The flaw exists because mod_hdcp_hdcp1_enable_encryption() calls get_first_active_display() without validating its return value, which can be NULL when the display list is empty, leading to a NULL pointer dereference in mod_hdcp_hdcp2_enable_encryption(). Affected kernel versions span 5.8 through 6.15.4 across multiple stable branches. It was published on July 25, 2025, and carries a CVSS v3.1 base score of 5.5 (Medium) (Red Hat CVE, Feedly).

The root cause is classified as CWE-476 (NULL Pointer Dereference). Within the drm/amd/display kernel module, the function mod_hdcp_hdcp1_enable_encryption() invokes get_first_active_display() to retrieve the first active display from a list, but omits a NULL check on the returned pointer. If no active displays are present (i.e., the display list is empty), the returned NULL pointer is subsequently dereferenced in mod_hdcp_hdcp2_enable_encryption(), triggering a kernel panic. The attack vector is local, requiring low privileges and no user interaction. The fix adds an explicit NULL check and returns MOD_HDCP_STATUS_DISPLAY_NOT_FOUND when the function returns NULL (Red Hat CVE, Kernel Patch).

Successful exploitation results in a kernel panic or system crash, causing a denial of service (DoS) on the affected host. There is no impact on confidentiality or data integrity — the vulnerability is limited to availability. Systems running AMD GPUs with HDCP-capable display configurations are most at risk, particularly in scenarios where display connections are manipulated or absent (Red Hat CVE, Feedly).

There is no public proof-of-concept exploit and no evidence of in-the-wild exploitation as of the time of writing. The EPSS score is approximately 0.014% (0.000140), indicating very low probability of exploitation in the near term. The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. Exploitation requires local access with low-privilege permissions, limiting the practical attack surface (Feedly, Red Hat CVE).

Patches have been backported to multiple stable Linux kernel branches. The fixed versions are: 5.15.187, 6.1.143, 6.6.96, 6.12.36, 6.15.5, and 6.16-rc1. Users should update to the appropriate patched kernel version for their distribution. Ubuntu has issued security notices (USN-7774-1, USN-7774-3, USN-7774-5, USN-7775-1, USN-7775-3, USN-7833-1 through USN-7833-4) addressing this and related vulnerabilities. As a temporary workaround where patching is not immediately possible, restricting local user access and monitoring for unusual kernel behavior is advised (Ubuntu USN-7774-1, Red Hat CVE, Kernel Patch).

The vulnerability received routine coverage from Linux security tracking sites and distribution security teams. Ubuntu issued multiple security notices across different kernel flavors (generic, Azure FIPS, Oracle, GCP, Nvidia Tegra IGX), indicating broad distribution-level attention. No notable independent researcher commentary or significant social media discussion has been identified beyond standard vulnerability tracking (Ubuntu USN-7774-1, Ubuntu USN-7833-1).