CVE-2026-98747 serial: core: fix NULL pointer dereference in serial_core_unregister_port()
A local attacker with high privileges can trigger a NULL pointer dereference in the Linux kernel serial core, causing a system crash.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98747?
CVE-2026-98747 is a vulnerability in Linux, published on 18 Oct 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:
serial: core: fix NULL pointer dereference in serial_core_unregister_port()
port->port_dev is NULL when no port device is installed: it is cleared on teardown, and never set if registration failed before serial_core_port_device_add(). serial_core_unregister_port() passes it straight to serial_core_get_ctrl_dev(), which dereferences it:
KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047] RIP: serial_core_unregister_port Call Trace: serial8250_unregister_port serial8250_remove unbind_store
Return early when there is no port device, and read port->port_dev under port_mutex.
Also clear port->port_dev on the serial_core_register_port() error path, where the port device has already been removed.
Which versions are affected by CVE-2026-98747?
How do I fix CVE-2026-98747?
Apply the vendor's patch.
Is CVE-2026-98747 being exploited?
There is no known exploitation of CVE-2026-98747 in the wild and no public exploit code.
Sources
Also known as AZL-109137, BELL-CVE-2026-98747, DEBIAN-CVE-2026-98747, GHSA-6854-f26p-xx8r, UBUNTU-CVE-2026-98747.