{"id":"CVE-2026-98695","kind":"vulnerability","aliases":["CVE-2026-98695"],"related":[],"title":"Linux kernel USB serial: ioctl race with hangup causes NULL dereference","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nUSB: serial: fix ioctl hangup race\n\nThe tty ioctls can race with hangup and end up calling into a tty driver\nfor a device that is already gone or powered down.\n\nSerialise the callbacks using the tty port mutex and add the missing\nchecks to make sure the port has not been hung up before accessing port\ndriver data or hardware.\n\nThis specifically avoids dereferencing a NULL-pointer if a device is\ndisconnected during lengthy break signalling.\n\nNote that TIOCGICOUNT and TIOCMIWAIT do not access port driver data or\nhardware and are therefore not affected by the race.","summary":"A race between tty ioctls and device hangup in the Linux kernel USB serial driver lets an ioctl call into a driver for a device that is already disconnected. The sources describe this as a NULL-pointer dereference when a device is removed during lengthy break signalling.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","linux","usb-serial"],"not_affected_if":[],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-10-18T16:17:22+00:00","first_seen_at":"2026-10-23T21:57:16+00:00","triaged_at":"2026-10-25T05:18:59+00:00","updated_at":"2026-10-25T05:18:59+00:00","category":"infrastructure","confidence":0.4,"triage":{"at":"2026-10-25T05:18:59Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Linux kernel USB serial: ioctl race with hangup causes NULL dereference","impact":"low","summary":"A race between tty ioctls and device hangup in the Linux kernel USB serial driver lets an ioctl call into a driver for a device that is already disconnected. The sources describe this as a NULL-pointer dereference when a device is removed during lengthy break signalling.","category":"infrastructure","nicknames":[],"who_cares":["linux","usb-serial"],"confidence":0.4,"needs_auth":"unknown","worst_case":"unknown; the sources describe a kernel NULL-pointer dereference, with no code execution stated","analyst_note":"Check the upstream kernel commit and the NVD entry for affected kernel version ranges, fixed versions and whether a crash is the only impact.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":[],"who_is_affected":"unknown","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.00053,"input_tokens":3433,"output_tokens":373,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-98695':14A,17A 'access':136C,166C 'add':121C 'affect':176C 'alreadi':50B,107C 'avoid':144C 'break':69B,157C 'call':41B,97C 'callback':114C 'caus':9A 'check':124C 'cve':12A,15A 'data':139C,169C 'derefer':11A,61B 'dereferenc':145C 'describ':54B 'devic':29B,47B,64B,104C,152C 'disconnect':51B,154C 'driver':37B,44B,101C,138C,168C 'end':95C 'fix':83C 'follow':76C 'gone':108C 'hangup':8A,30B,85C,93C 'hardwar':141C,171C 'hung':133C 'infrastructur':18B 'ioctl':5A,27B,40B,84C,89C 'kernel':2A,34B,74C 'lengthi':68B,156C 'let':38B 'linux':1A,19B,33B,73C 'make':126C 'miss':123C 'mutex':119C 'note':159C 'null':10A,59B,148C 'null-point':58B,147C 'pointer':60B,149C 'port':118C,129C,137C,167C 'power':110C 'race':6A,24B,86C,91C,179C 'remov':66B 'resolv':80C 'serial':4A,22B,36B,82C 'serialis':112C 'signal':70B,158C 'sourc':53B 'specif':143C 'sure':127C 'therefor':174C 'tiocgicount':161C 'tiocmiwait':163C 'tti':26B,88C,100C,117C 'usb':3A,21B,35B,81C 'usb-seri':20B 'use':115C 'vulner':77C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:17:22+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98695","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98695","severity":null,"published_at":"2026-10-18T16:17:22+00:00","modified_at":"2026-10-21T13:21:37+00:00","first_seen_at":"2026-10-23T21:57:16+00:00","fetched_at":"2026-10-23T22:28:56+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"}