CVE-2026-74424 fbcon: fix NULL pointer dereference for a console without vc_data
A local attacker can cause a denial of service in the Linux kernel by triggering a NULL pointer dereference in the framebuffer console driver.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74424?
CVE-2026-74424 is a vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-74424?
How do I fix CVE-2026-74424?
Apply the vendor's patch.
Is CVE-2026-74424 being exploited?
There is no known exploitation of CVE-2026-74424 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74424, DEBIAN-CVE-2026-74424, GHSA-wq9g-885w-mm9h, UBUNTU-CVE-2026-74424.