CVE-2023-53833: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53833 is a NULL pointer dereference vulnerability in the Linux kernel's DRM/i915 (Intel graphics) subsystem. The flaw exists in the intel_atomic_get_new_crtc_state function, which can return NULL if the CRTC state was not previously obtained via intel_atomic_get_crtc_state, and the return value was not checked before use. The vulnerability was published on December 9, 2025, and affects Linux kernel versions from commit 74a75dc908692dd0548209004e53832c02433c0c up to the patched commits in stable branches. It carries an estimated CVSS severity of Medium, with an EPSS score of approximately 0.017% (Feedly, EUVD).

The root cause is a missing NULL pointer check (CWE-476) in the Linux kernel's drm/i915 driver. The function intel_atomic_get_new_crtc_state can legitimately return NULL when the CRTC state has not been previously acquired through intel_atomic_get_crtc_state, but the calling code dereferences the returned pointer without validation. The fix, cherry-picked from upstream commit 1d5b09f8daf859247a1ea65b0d732a24d88980d8, adds a NULL check consistent with other locations in the codebase that handle the same condition. Exploitation requires local access to a system running a vulnerable kernel with Intel graphics hardware (Feedly, EUVD).

Successful triggering of this vulnerability causes a kernel NULL pointer dereference, which typically results in a kernel panic (system crash) and denial of service. Because the flaw resides in the DRM/i915 graphics subsystem, it primarily affects systems with Intel integrated or discrete graphics. There is no evidence of confidentiality or integrity impact beyond availability loss; lateral movement or data exfiltration are not expected outcomes of this vulnerability (Feedly).

The vulnerability is fixed in Linux kernel stable branches via the following commits: dbf25cc21beff4fd2e730573845a266504b21bb2, 8b3c0d2d1685ba40b0af4ee1f8d8824a73870f88, and a41d985902c153c31c616fe183cf2ee331e95ecb. Patched versions include Linux 6.1.30, 6.3.4, and 6.4 and later. Red Hat has issued multiple errata addressing this CVE, including RHSA-2026:2490, RHSA-2026:2535, RHSA-2026:2560, RHSA-2026:2577, RHSA-2026:2583, RHSA-2026:2664, and RHSA-2026:3360. Users should update to a patched kernel version as provided by their Linux distribution (Feedly, Red Hat RHSA-2026:2490).