CVE-2026-31605 fbdev: udlfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO

Medium 5.5 Published Updated

A divide-by-zero error in the udlfb driver allows local attackers to crash the system via FBIOPUT_VSCREENINFO ioctl calls.

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-2026-31605?

CVE-2026-31605 is a medium-severity denial of service vulnerability in Linux kernel, published on 24 Apr 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:

fbdev: udlfb: avoid divide-by-zero on FBIOPUT_VSCREENINFO

Much like commit 19f953e74356 ("fbdev: fb_pm2fb: Avoid potential divide by zero error"), we also need to prevent that same crash from happening in the udlfb driver as it uses pixclock directly when dividing, which will crash.

Weakness: CWE-369

Which versions are affected by CVE-2026-31605?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-31605?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-31605 being exploited?

There is no known exploitation of CVE-2026-31605 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as AZL-83687, BELL-CVE-2026-31605, DEBIAN-CVE-2026-31605, GHSA-5j7x-34ch-2fxf, ROOT-OS-DEBIAN-11-CVE-2026-31605, ROOT-OS-DEBIAN-12-CVE-2026-31605 and 3 more.

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