CVE-2026-43458

Description

In the Linux kernel, the following vulnerability has been resolved: serial: caif: hold tty->link reference in ldisc_open and ser_release A reproducer triggers a KASAN slab-use-after-free in pty_write_room() when caif_serial's TX path calls tty_write_room(). The faulting access is on tty->link->port. Hold an extra kref on tty->link for the lifetime of the caif_serial line discipline: get it in ldisc_open() and drop it in ser_release(), and also drop it on the ldisc_open() error path. With this change applied, the reproducer no longer triggers the UAF in my testing.

References

• https://git.kernel.org/stable/c/23a3ac2e2262a291498567418227b99e1f3606b1
• https://git.kernel.org/stable/c/27e43356d0defb9fc7fa25265219a3ffeb7b3e98
• https://git.kernel.org/stable/c/288598d80a068a0e9281de35bcb4ce495f189e2a
• https://git.kernel.org/stable/c/35b58d3bc716ebb9ebd10fe1cac8c1177242511c
• https://git.kernel.org/stable/c/52135420e9f75853ea0c6cea7b736e3e98495f7d