CVE-2026-72238 x86/boot: Validate console=uart8250 baud rate to fix early boot hang
An attacker with local access or control over boot parameters can cause a system hang during early boot by specifying an invalid UART baud rate.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72238?
CVE-2026-72238 is a denial of service 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:
x86/boot: Validate console=uart8250 baud rate to fix early boot hang
When the baud rate is empty, 0, invalid, or overflows to 0 when stored as an int, the system will hang during early boot because of a division by zero in early_serial_init().
Fall back to DEFAULT_BAUD when the resulting baud rate is 0 to prevent an early system hang.
Which versions are affected by CVE-2026-72238?
How do I fix CVE-2026-72238?
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-2026-72238 being exploited?
There is no known exploitation of CVE-2026-72238 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72238, DEBIAN-CVE-2026-72238, GHSA-phw4-wh3r-2wj6, UBUNTU-CVE-2026-72238.