{"id":"CVE-2026-98883","kind":"vulnerability","aliases":["CVE-2026-98883"],"related":[],"title":"Linux kernel: serial 8250 driver warns on MIPS Alchemy UART type","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nserial: 8250_port: recognize UPIO_AU\n\nMy MIPS Alchemy systems generate the following warning during\nprobe of the 8250 driver:\n\nWARNING: drivers/tty/serial/8250/8250_port.c:462 at set_io_from_upio+0xfc/0x124, CPU#0: swapper/0/1\nUnsupported UART type 4\n[...]\n[<80521d40>] set_io_from_upio+0xfc/0x124\n[<80521dfc>] serial8250_set_defaults+0x94/0xe0\n[<80520fb4>] serial8250_register_8250_port+0x288/0x51c\n[<805214ec>] serial8250_probe+0x160/0x1e8\n[<8053b5f0>] platform_probe+0x64/0x90\n\nThe least invasive fix is to recognize UPIO_AU (type 4) in set_io_from_upio()\nand do nothing, since all parameters have already been set up in\n8250_rt288x.c::au_platform_setup().\n\nRun-tested on Alchemy Au1300 platform.","summary":"The Linux kernel 8250 serial driver did not recognize the UPIO_AU port type used on MIPS Alchemy systems, so it printed a kernel warning during probe. The fix makes the driver accept that type and skip the step, which only affects boot logs on those boards.","severity":"unknown","cvss":null,"epss":0.00198,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["linux-kernel","mips-alchemy","runtime"],"not_affected_if":["non-mips-alchemy-hardware"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-10-23T12:18:21+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","triaged_at":"2026-10-25T05:00:08+00:00","updated_at":"2026-10-25T12:38:51+00:00","category":"runtime","confidence":0.4,"triage":{"at":"2026-10-25T05:00:08Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Linux kernel: serial 8250 driver warns on MIPS Alchemy UART type","impact":"low","summary":"The Linux kernel 8250 serial driver did not recognize the UPIO_AU port type used on MIPS Alchemy systems, so it printed a kernel warning during probe. The fix makes the driver accept that type and skip the step, which only affects boot logs on those boards.","category":"runtime","nicknames":[],"who_cares":["linux-kernel","mips-alchemy"],"confidence":0.4,"needs_auth":"unknown","worst_case":"unknown","analyst_note":"","how_to_check":"unknown","needs_analyst":false,"not_affected_if":["non-mips-alchemy-hardware"],"who_is_affected":"Only MIPS Alchemy systems (such as Au1300 boards) that load the 8250 serial driver are described by the sources; the sources do not describe a security impact beyond a warning message. unknown for anyone else.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"low"},"cost_usd":0.000553,"input_tokens":3595,"output_tokens":388,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'+0':110C,124C,130C,137C,142C,147C '-2026':13A,16A '-98883':14A,17A '0':113C '4':118C,159C '462':104C '80520fb4':132C '805214ec':139C '80521d40':119C '80521dfc':126C '8053b5f0':144C '8250':4A,28B,83C,100C,135C,177C 'accept':57B 'affect':66B 'alchemi':9A,23B,42B,90C,186C 'alreadi':172C 'au':36B,87C,157C,179C 'au1300':187C 'board':71B 'boot':67B 'cpu':112C 'cve':12A,15A 'default':129C 'driver':5A,30B,56B,101C 'drivers/tty/serial/8250/8250_port.c':103C 'fix':53B,152C 'follow':77C,94C 'generat':92C 'invas':151C 'io':107C,121C,162C 'kernel':2A,20B,27B,48B,75C 'least':150C 'linux':1A,19B,26B,74C 'linux-kernel':18B 'log':68B 'make':54B 'mip':8A,22B,41B,89C 'mips-alchemi':21B 'noth':167C 'paramet':170C 'platform':145C,180C,188C 'port':37B,84C,136C 'print':46B 'probe':51B,97C,141C,146C 'recogn':33B,85C,155C 'regist':134C 'resolv':81C 'rt288x.c':178C 'run':183C 'run-test':182C 'runtim':24B 'serial':3A,29B,82C 'serial8250':127C,133C,140C 'set':106C,120C,128C,161C,174C 'setup':181C 'sinc':168C 'skip':61B 'step':63B 'swapper/0/1':114C 'system':43B,91C 'test':184C 'type':11A,38B,59B,117C,158C 'uart':10A,116C 'unsupport':115C 'upio':35B,86C,109C,123C,156C,164C 'use':39B 'vulner':78C 'warn':6A,49B,95C,102C 'x160/0x1e8':143C 'x288/0x51c':138C 'x64/0x90':148C 'x94/0xe0':131C 'xfc/0x124':111C,125C","nicknames":[],"mitigations":[],"who_affected":"Only MIPS Alchemy systems (such as Au1300 boards) that load the 8250 serial driver are described by the sources; the sources do not describe a security impact beyond a warning message. unknown for anyone else.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-23T12:18:21+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98883","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98883","severity":null,"published_at":"2026-10-23T12:18:21+00:00","modified_at":"2026-10-23T12:18:21+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","fetched_at":"2026-10-23T22:29:03+00:00","note":null},{"source":"epss","external_id":"CVE-2026-98883","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-98883","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-25T12:38:51+00:00","fetched_at":"2026-10-25T12:38:51+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}