Linux Kernel 8250 Port: Recognize UPIO_AU UART Type 4
CVE-2026-98883 Published on October 23, 2026
serial: 8250_port: recognize UPIO_AU
In the Linux kernel, the following vulnerability has been resolved:
serial: 8250_port: recognize UPIO_AU
My MIPS Alchemy systems generate the following warning during
probe of the 8250 driver:
WARNING: drivers/tty/serial/8250/8250_port.c:462 at set_io_from_upio+0xfc/0x124, CPU#0: swapper/0/1
Unsupported UART type 4
[...]
[<80521d40>] set_io_from_upio+0xfc/0x124
[<80521dfc>] serial8250_set_defaults+0x94/0xe0
[<80520fb4>] serial8250_register_8250_port+0x288/0x51c
[<805214ec>] serial8250_probe+0x160/0x1e8
[<8053b5f0>] platform_probe+0x64/0x90
The least invasive fix is to recognize UPIO_AU (type 4) in set_io_from_upio()
and do nothing, since all parameters have already been set up in
8250_rt288x.c::au_platform_setup().
Run-tested on Alchemy Au1300 platform.
Products Associated with CVE-2026-98883
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Affected Versions
Linux:- Version 7c7e6c8924e7bf98db4e5b2edb202842003c00c2 and below 9f67997353caa29c6a080789a1fb6e01fb50c118 is affected.
- Version 7c7e6c8924e7bf98db4e5b2edb202842003c00c2 and below 49fa670efdfdd27e29145cbd2beef065c08717ef is affected.
- Version 6.13 is affected.
- Before 6.13 is unaffected.
- Version 6.18.53, <= 6.18.* is unaffected.
- Version 7.2, <= * is unaffected.