Linux kernel 8250 serial driver warns on unrecognized UPIO_AU type
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from CNA.
Summary
The Linux kernel from 6.13 has a flaw in its 8250 serial port driver, which does not recognize the UPIO_AU port type. On MIPS Alchemy systems, probing the driver logs an unsupported UART type warning. The fix treats UPIO_AU as already configured by the platform setup code.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
Description from the CNA
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
Fixed versions are Linux kernel 6.18.53 and 7.2.
Written with Claude Haiku 5.5 from the sources below · 2026-11-06
- Fix · CNA Linux (Linux) Fixed in 6.18.53, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 6 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-23 Threatist record created from CVE-2026-98883
- 2026-10-23 Alias added: GHSA-g9xp-whrx-5gjh
- 2026-10-26 Fix available: Linux/Linux@0 · CNA
- 2026-10-26 Affected versions changed · Red Hat
- 2026-10-26 CVSS score added · Red Hat
References
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Sources
- CVE-2026-98883 · CVE Program
- CVE-2026-98883 · NVD
- FIRST EPSS
- GHSA-g9xp-whrx-5gjh · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98883 · Red Hat security data · CC BY 4.0
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