CVE-2026-74424

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

fbcon: fix NULL pointer dereference for a console without vc_data

fbcon_new_modelist() runs when a framebuffer's modelist changes. For each

console mapped to it with fb_display[i].mode set, it reads vc_cons[i].d and

passes the vc_num to fbcon_set_disp(). This assumes a console with a mode

set has a vc_data, but it can be NULL. fbcon_set_disp() sets

fb_display[i].mode before it checks vc_data, and fbcon_deinit() leaves the

mode set after the vc_data is freed. fbcon_new_modelist() then dereferences

the NULL vc_data.

Keep fb_display[i].mode set only while the console has a vc_data. Check

vc_data before setting the mode in fbcon_set_disp(), and clear the mode in

fbcon_deinit(). The existing mode check in fbcon_new_modelist() then skips

such consoles.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References