{"id":"CVE-2026-98765","kind":"vulnerability","aliases":["CVE-2026-98765"],"related":[],"title":"Linux kernel: USB dummy-hcd gadget unbind can race pending request completions","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nUSB: gadget: dummy-hcd: Fix wait for outstanding request completions\n\nThe dummy-hcd driver emulates synchronize_irq() by waiting until its\nprivate callback_usage counter drops to 0 (with the private lock not\nheld).  This counter is incremented whenever a gadget driver callback\noccurs (which requires the private lock to be dropped), but not when a\nrequest completion handler is called.\n\nThis is an oversight.  Request completion is triggered by timer\ninterrupts (emulating device IRQs in a real UDC), and the interrupt\nhandlers are supposed to have completed when the synchronize_irq()\nemulation routine returns -- they aren't supposed to be in the middle\nof a completion callback.  If this happens it can lead to a gadget\ndriver's unbind routine running before all outstanding request\ncompletions have finished, maybe even allowing the gadget driver's\nmodule to be unloaded while a completion handler is still running.\n\nFix the oversight by incrementing the callback_usage value across\nrequest completion callbacks.","summary":"The dummy-hcd USB gadget emulator's synchronize routine did not wait for in-flight request completion handlers, so a gadget driver could unbind or unload while a completion callback was still running. The sources do not describe a remote or attacker-controlled trigger; the flaw is a use-after-unbind race in a test/emulation driver.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["kernel","linux","runtime","usb-gadget"],"not_affected_if":["default-config"],"how_to_check":"- unknown","fix":"- unknown","status":"open","published_at":"2026-10-18T16:17:30+00:00","first_seen_at":"2026-10-23T21:57:16+00:00","triaged_at":"2026-10-25T05:16:40+00:00","updated_at":"2026-10-25T05:16:40+00:00","category":"runtime","confidence":0.5,"triage":{"at":"2026-10-25T05:16:40Z","model":"claude-haiku-5-5","output":{"fix":"- unknown","reach":"local","title":"Linux kernel: USB dummy-hcd gadget unbind can race pending request completions","impact":"low","summary":"The dummy-hcd USB gadget emulator's synchronize routine did not wait for in-flight request completion handlers, so a gadget driver could unbind or unload while a completion callback was still running. The sources do not describe a remote or attacker-controlled trigger; the flaw is a use-after-unbind race in a test/emulation driver.","category":"runtime","nicknames":[],"who_cares":["linux","kernel","usb-gadget"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown","analyst_note":"Check the kernel stable commit referenced by NVD for the fixed kernel versions and whether dummy-hcd is built in distro kernels.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["default-config"],"who_is_affected":"unknown","user_interaction":"unknown","needs_special_setup":"yes","severity_if_unknown":"low"},"cost_usd":0.000545,"input_tokens":3574,"output_tokens":376,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-98765':16A,19A '0':125C 'across':254C 'allow':229C 'aren':194C 'attack':70B 'attacker-control':69B 'call':158C 'callback':57B,120C,140C,205C,251C,257C 'complet':13A,44B,56B,106C,155C,164C,185C,204C,224C,240C,256C 'control':71B 'could':50B 'counter':122C,133C 'cve':14A,17A 'describ':65B 'devic':171C 'driver':49B,85B,111C,139C,215C,232C 'drop':123C,149C 'dummi':5A,28B,99C,109C 'dummy-hcd':4A,27B,98C,108C 'emul':32B,112C,170C,190C 'even':228C 'finish':226C 'fix':101C,245C 'flaw':74B 'flight':42B 'follow':91C 'gadget':7A,25B,31B,48B,97C,138C,214C,231C 'handler':45B,156C,180C,241C 'happen':208C 'hcd':6A,29B,100C,110C 'held':131C 'in-flight':40B 'increment':135C,249C 'interrupt':169C,179C 'irq':114C,172C,189C 'kernel':2A,20B,89C 'lead':211C 'linux':1A,21B,88C 'lock':129C,146C 'mayb':227C 'middl':201C 'modul':234C 'occur':141C 'outstand':104C,222C 'oversight':162C,247C 'pend':11A 'privat':119C,128C,145C 'race':10A,81B 'real':175C 'remot':67B 'request':12A,43B,105C,154C,163C,223C,255C 'requir':143C 'resolv':95C 'return':192C 'routin':35B,191C,218C 'run':60B,219C,244C 'runtim':22B 'sourc':62B 'still':59B,243C 'suppos':182C,196C 'synchron':34B,113C,188C 'test/emulation':84B 'timer':168C 'trigger':72B,166C 'udc':176C 'unbind':8A,51B,80B,217C 'unload':53B,237C 'usag':121C,252C 'usb':3A,24B,30B,96C 'usb-gadget':23B 'use':78B 'use-after-unbind':77B 'valu':253C 'vulner':92C 'wait':38B,102C,116C 'whenev':136C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:17:30+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98765","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98765","severity":null,"published_at":"2026-10-18T16:17:30+00:00","modified_at":"2026-10-21T13:21:44+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"}