{"id":"CVE-2026-99050","kind":"vulnerability","aliases":["CVE-2026-99050"],"related":[],"title":"Linux kernel GPIO MPSSE driver: race lets a USB unplug cause use-after-free","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ngpio: mpsse: fix race when arming the IRQ poll worker\n\ngpio_mpsse_irq_enable() arms the poll worker before publishing it:\nschedule_work() runs before the worker is added to priv->workers. If\ngpio_mpsse_disconnect() walks the list in that window it misses the\nworker, and once disconnect returns, the USB core frees mpsse_priv\nwhile the orphaned gpio_mpsse_poll() work keeps accessing it, causing\na use-after-free.\n\nFix this by publishing and arming the worker in one irq_spin\ncritical section. Teardown walks the same list under irq_spin, so a\nworker found on the list is guaranteed to be armed, and\ncancel_work_sync() handles it whether it is queued or running.\n\nA worker armed after the disconnect walk would still be missed, so\nalso set a new priv->dying flag under irq_spin before the teardown\nwalk, and check it in the same critical section, freeing it via\nkfree_rcu() instead when the device is going away, since kfree()\nwould be called with the IRQ core's raw spinlock held and may sleep\non PREEMPT_RT. schedule_work() is safe to call with irq_spin held,\nand the next probe gets a fresh mpsse_priv, so the flag never needs\nto be cleared.\n\nThis issue was found by an in-house static analysis tool.","summary":"In the Linux kernel's GPIO MPSSE driver, the IRQ poll worker can be armed after the disconnect teardown has already scanned for workers, so the worker keeps running on freed memory. The sources describe a use-after-free in the kernel's USB-attached MPSSE GPIO path; they do not state what an attacker can do with it.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["gpio-mpsse","linux-kernel","package","usb"],"not_affected_if":["no-mpsse-usb-adapter"],"how_to_check":"- unknown","fix":"- Update the Linux kernel to a release that includes the upstream commit fixing gpio: mpsse IRQ poll worker arming (the sources do not name the version).","status":"open","published_at":"2026-10-23T13:17:28+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","triaged_at":"2026-10-25T04:54:05+00:00","updated_at":"2026-10-25T04:54:05+00:00","category":"package","confidence":0.5,"triage":{"at":"2026-10-25T04:54:05Z","model":"claude-haiku-5-5","output":{"fix":"- Update the Linux kernel to a release that includes the upstream commit fixing gpio: mpsse IRQ poll worker arming (the sources do not name the version).","reach":"local","title":"Linux kernel GPIO MPSSE driver: race lets a USB unplug cause use-after-free","impact":"medium","summary":"In the Linux kernel's GPIO MPSSE driver, the IRQ poll worker can be armed after the disconnect teardown has already scanned for workers, so the worker keeps running on freed memory. The sources describe a use-after-free in the kernel's USB-attached MPSSE GPIO path; they do not state what an attacker can do with it.","category":"package","nicknames":[],"who_cares":["linux-kernel","gpio-mpsse","usb"],"confidence":0.5,"needs_auth":"unknown","worst_case":"unknown","analyst_note":"Check the kernel.org stable commit for the gpio: mpsse fix to get the fixed version numbers and whether an attacker can trigger the race with a USB device.","how_to_check":"- unknown","needs_analyst":true,"not_affected_if":["no-mpsse-usb-adapter"],"who_is_affected":"Systems running a Linux kernel with the gpio-mpsse driver, which handles FTDI MPSSE USB adapters with GPIO and interrupt lines. The sources do not say how exposed a typical machine is, or whether an attacker must be able to plug in a device.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.00064,"input_tokens":3685,"output_tokens":543,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':17A,20A '-99050':18A,21A 'access':161C 'add':125C 'alreadi':50B 'also':227C 'analysi':317C 'arm':44B,102C,111C,174C,202C,217C 'attach':76B 'attack':86B 'away':260C 'call':265C,285C 'cancel':204C 'caus':11A,163C 'check':242C 'clear':306C 'core':149C,269C 'critic':181C,247C 'cve':16A,19A 'describ':64B 'devic':257C 'die':232C 'disconnect':47B,132C,145C,220C 'driver':5A,37B 'enabl':110C 'fix':99C,169C 'flag':233C,301C 'follow':92C 'found':194C,310C 'free':15A,69B,150C,168C,249C 'freed':60B 'fresh':296C 'get':294C 'go':259C 'gpio':3A,23B,35B,78B,97C,107C,130C,156C 'gpio-mpss':22B 'guarante':199C 'handl':207C 'held':273C,289C 'hous':315C 'in-hous':313C 'instead':254C 'irq':39B,104C,109C,179C,189C,235C,268C,287C 'issu':308C 'keep':57B,160C 'kernel':2A,27B,33B,72B,90C 'kfree':252C,262C 'let':7A 'linux':1A,26B,32B,89C 'linux-kernel':25B 'list':135C,187C,197C 'may':275C 'memori':61B 'miss':140C,225C 'mpsse':4A,24B,36B,77B,98C,108C,131C,151C,157C,297C 'need':303C 'never':302C 'new':230C 'next':292C 'one':178C 'orphan':155C 'packag':28B 'path':79B 'poll':40B,105C,113C,158C 'preempt':278C 'priv':127C,152C,231C,298C 'probe':293C 'publish':116C,172C 'queu':212C 'race':6A,100C 'raw':271C 'rcu':253C 'resolv':96C 'return':146C 'rt':279C 'run':58B,120C,214C 'safe':283C 'scan':51B 'schedul':118C,280C 'section':182C,248C 'set':228C 'sinc':261C 'sleep':276C 'sourc':63B 'spin':180C,190C,236C,288C 'spinlock':272C 'state':83B 'static':316C 'still':223C 'sync':206C 'teardown':48B,183C,239C 'tool':318C 'unplug':10A 'usb':9A,29B,75B,148C 'usb-attach':74B 'use':13A,67B,166C 'use-after-fre':12A,66B,165C 'via':251C 'vulner':93C 'walk':133C,184C,221C,240C 'whether':209C 'window':138C 'work':119C,159C,205C,281C 'worker':41B,53B,56B,106C,114C,123C,128C,142C,176C,193C,216C 'would':222C,263C","nicknames":[],"mitigations":[],"who_affected":"Systems running a Linux kernel with the gpio-mpsse driver, which handles FTDI MPSSE USB adapters with GPIO and interrupt lines. The sources do not say how exposed a typical machine is, or whether an attacker must be able to plug in a device.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-23T13:17:28+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-99050","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-99050","severity":null,"published_at":"2026-10-23T13:17:28+00:00","modified_at":"2026-10-23T13:17:28+00:00","first_seen_at":"2026-10-23T21:57:33+00:00","fetched_at":"2026-10-23T22:29:03+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"}