CVE-2026-97480 tty: serial: 8250: protect against NULL uart->port.dev in register
A NULL pointer dereference in the Linux kernel 8250 serial driver can cause a system crash when registering ports without a parent device.
- 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-2026-97480?
CVE-2026-97480 is a vulnerability in Linux, published on 24 Sep 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:
tty: serial: 8250: protect against NULL uart->port.dev in register
serial8250_register_8250_port() conditionally copies uart->port.dev from up->port.dev only when up->port.dev is non-NULL:
if (up->port.dev) { uart->port.dev = up->port.dev; ... }
So if both the existing uart slot and up have a NULL ->dev, uart->port.dev remains NULL. The very next ACPI companion check then dereferences it unconditionally:
if (!has_acpi_companion(uart->port.dev)) {
has_acpi_companion() reads dev->fwnode without a NULL guard (include/linux/acpi.h), so this NULL-derefs the kernel for the remaining no-dev case rather than just skipping the mctrl_gpio_init() initialisation as intended.
smatch flags the inconsistency:
drivers/tty/serial/8250/8250_core.c:767 serial8250_register_8250_port() error: 'uart->port.dev' could be null (see line 719)
Guard the call with a NULL check so register continues to work for callers that legitimately have no parent device (legacy non-OF/non-ACPI registrations).
No functional change for callers that pass a non-NULL ->dev.
Which versions are affected by CVE-2026-97480?
How do I fix CVE-2026-97480?
Apply the vendor's patch.
Is CVE-2026-97480 being exploited?
There is no known exploitation of CVE-2026-97480 in the wild and no public exploit code.
Sources
Also known as AZL-103814, BELL-CVE-2026-97480, DEBIAN-CVE-2026-97480, GHSA-jrxp-w58r-g8c9, UBUNTU-CVE-2026-97480.