Junglewise Threat Intelligence

CVE-2025-39675: Linux Kernel NULL pointer dereference in AMD display driver

CVE-2025-39675 · Severity: medium · CVSS 5.5 · Published 2025-09-05

Technologies: Linux Kernel. Vendors: Linux.

Executive brief

A vulnerability in the Linux kernel's AMD display driver could allow a local user to crash the system. The issue occurs when the system attempts to manage High-bandwidth Digital Content Protection (HDCP) for displays, but fails to handle cases where no active displays are found. This can lead to a system instability or a complete kernel crash (denial of service).

Technical details

A NULL pointer dereference vulnerability exists in the Linux kernel's AMD display driver (drm/amd/display) within the mod_hdcp_hdcp1_create_session() function. The root cause is a failure to validate the return value of get_first_active_display(), which returns NULL if the display list is empty. An attacker with local access could potentially trigger this condition to cause a kernel oops and denial of service. The issue has been resolved by adding a null pointer check that returns MOD_HDCP_STATUS_DISPLAY_NOT_FOUND when no active display is detected. Fixes have been backported to multiple stable kernel branches including 5.15.y, 6.1.y, 6.6.y, 6.12.y, and 6.16.y.

Affected products

  • Linux Linux Kernel 5.8 to 5.15.190, 5.16 to 6.1.149, 6.2 to 6.6.103, 6.7 to 6.12.44, 6.13 to 6.16.4

Timeline

  • 2025-07-23: other: Vulnerability fixed in upstream code
  • 2025-09-05: disclosed: NVD Published Date
  • 2025-09-05: advisory: CVE-2025-39675 published by kernel.org

References

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