{"id":"CVE-2026-98761","kind":"vulnerability","aliases":["CVE-2026-98761"],"related":[],"title":"Linux kernel USB Type-C: failed fast role swap leaves VBUS powered","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: typec: tcpm: recover after failure to start the frs ams\n\nReset the port if the tcpm fails to start the FAST_ROLE_SWAP AMS by\ninitiating error recovery on it.\n\nThis helps in cases where some cables (incorrectly) signal an FRS to\nan FRS capable port during disconnection. The TCPC autonomously starts\nsourcing VBUS on detecting the FRS signal. However, the VBUS sourcing is\nleft on when the FAST_ROLE_SWAP AMS fails to start (as tcpm_sink_tx_ok\nis 0 as CC is open due to the cable disconnect). This is because the\ncode sets the state to INVALID_STATE without resetting the port state.\n\nLog snippet before changes:\n[  101.401960] AMS FAST_ROLE_SWAP start\n[  101.401971] Sink TX No Go\n[  101.401982] sourcing vbus\n[  101.401987] VBUS on\n[  101.402159] VBUS on\n[  109.257809] CC1: 0 -> 0, CC2: 5 -> 0 [state SNK_READY, polarity 1, disconnected]\n[  111.267442] VBUS on\n\nAfter changes:\n[   70.541211] AMS FAST_ROLE_SWAP start\n[   70.541220] Sink TX No Go\n[   70.541228] state change SNK_READY -> ERROR_RECOVERY [rev3 NONE_AMS]\n[   70.541362] VBUS on\n[   70.541365] sourcing vbus\n[   70.541367] VBUS on\n[   70.541374] state change ERROR_RECOVERY -> PORT_RESET [rev3 NONE_AMS]\n[   70.541410] disable vbus discharge ret:0\n[   70.543028] Setting usb_comm capable false\n[   70.544009] Setting voltage/current limit 0 mV 0 mA\n[   70.544034] polarity 0\n[   70.544239] Requesting mux state 0, usb-role 0, orientation 0\n[   70.555550] cc:=0\n[   70.555595] pending state change PORT_RESET -> PORT_RESET_WAIT_OFF @ 100 ms [rev3 NONE_AMS]\n[   70.555697] VBUS off\n[   70.555702] VBUS VSAFE0V\n[   70.555762] CC1: 5 -> 0, CC2: 0 -> 0 [state PORT_RESET, polarity 0, disconnected]\n[   70.587794] VBUS off\n[   70.587799] VBUS VSAFE0V\n[   70.655672] state change PORT_RESET -> PORT_RESET_WAIT_OFF [delayed 100 ms]\n[   70.655682] state change PORT_RESET_WAIT_OFF -> SNK_UNATTACHED [rev3 NONE_AMS]\n[   70.655686] Start toggling\n[   70.656274] CC1: 0 -> 0, CC2: 0 -> 0 [state TOGGLING, polarity 0, disconnected]","summary":"The Linux kernel's USB Type-C port manager (tcpm) could leave VBUS sourcing on after a Fast Role Swap failed to start, which happens when a faulty cable signals a Fast Role Swap during disconnection. The fix resets the port through error recovery so VBUS is turned off.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["embedded","infrastructure","linux-kernel","usb-typec"],"not_affected_if":[],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-10-18T16:17:29+00:00","first_seen_at":"2026-10-23T21:57:16+00:00","triaged_at":"2026-10-25T05:16:45+00:00","updated_at":"2026-10-25T05:16:45+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-10-25T05:16:45Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Linux kernel USB Type-C: failed fast role swap leaves VBUS powered","impact":"low","summary":"The Linux kernel's USB Type-C port manager (tcpm) could leave VBUS sourcing on after a Fast Role Swap failed to start, which happens when a faulty cable signals a Fast Role Swap during disconnection. The fix resets the port through error recovery so VBUS is turned off.","category":"infrastructure","nicknames":[],"who_cares":["linux-kernel","usb-typec","embedded"],"confidence":0.5,"needs_auth":"no","worst_case":"VBUS power stays on after cable disconnect, causing port misbehavior","analyst_note":"Check the kernel stable commit and affected version ranges via the NVD link; the sources give no CVSS score or exploit detail.","how_to_check":"unknown","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Systems running a Linux kernel with the USB Type-C tcpm driver that includes this change, such as devices with USB-C power delivery ports. The sources do not list affected kernel versions or say which hardware is most exposed.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000652,"input_tokens":4261,"output_tokens":451,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-98761':16A,19A '0':169C,221C,222C,225C,282C,293C,295C,299C,304C,308C,310C,313C,338C,340C,341C,346C,383C,384C,386C,387C,391C '1':230C '100':324C,364C '101.401960':199C '101.401971':205C '101.401982':210C '101.401987':213C '101.402159':216C '109.257809':219C '111.267442':232C '5':224C,337C '70.541211':237C '70.541220':243C '70.541228':248C '70.541362':258C '70.541365':261C '70.541367':264C '70.541374':267C '70.541410':277C '70.543028':283C '70.544009':289C '70.544034':297C '70.544239':300C '70.555550':311C '70.555595':314C '70.555697':329C '70.555702':332C '70.555762':335C '70.587794':348C '70.587799':351C '70.655672':354C '70.655682':366C '70.655686':378C '70.656274':381C 'am':97C,111C,159C,200C,238C,257C,276C,328C,377C 'autonom':138C 'c':6A,35B 'cabl':57B,124C,177C 'capabl':132C,287C 'case':121C 'cc':171C,312C 'cc1':220C,336C,382C 'cc2':223C,339C,385C 'chang':198C,236C,250C,269C,317C,356C,368C 'code':183C 'comm':286C 'could':39B 'cve':14A,17A 'delay':363C 'detect':143C 'disabl':278C 'discharg':280C 'disconnect':64B,135C,178C,231C,347C,392C 'due':174C 'embed':20B 'error':71B,114C,253C,270C 'fail':7A,49B,104C,160C 'failur':92C 'fals':288C 'fast':8A,46B,60B,108C,156C,201C,239C 'faulti':56B 'fix':66B 'follow':82C 'frs':96C,128C,131C,145C 'go':209C,247C 'happen':53B 'help':119C 'howev':147C 'incorrect':125C 'infrastructur':21B 'initi':113C 'invalid':188C 'kernel':2A,24B,30B,80C 'leav':11A,40B 'left':152C 'limit':292C 'linux':1A,23B,29B,79C 'linux-kernel':22B 'log':195C 'ma':296C 'manag':37B 'ms':325C,365C 'mux':302C 'mv':294C 'none':256C,275C,327C,376C 'ok':167C 'open':173C 'orient':309C 'pend':315C 'polar':229C,298C,345C,390C 'port':36B,69B,100C,133C,193C,272C,318C,320C,343C,357C,359C,369C 'power':13A 'readi':228C,252C 'recov':90C 'recoveri':72B,115C,254C,271C 'request':301C 'reset':67B,98C,191C,273C,319C,321C,344C,358C,360C,370C 'resolv':86C 'ret':281C 'rev3':255C,274C,326C,375C 'role':9A,47B,61B,109C,157C,202C,240C,307C 'set':184C,284C,290C 'signal':58B,126C,146C 'sink':165C,206C,244C 'snippet':196C 'snk':227C,251C,373C 'sourc':42B,140C,150C,211C,262C 'start':51B,94C,106C,139C,162C,204C,242C,379C 'state':186C,189C,194C,226C,249C,268C,303C,316C,342C,355C,367C,388C 'swap':10A,48B,62B,110C,158C,203C,241C 'tcpc':137C 'tcpm':38B,89C,103C,164C 'toggl':380C,389C 'turn':76B 'tx':166C,207C,245C 'type':5A,34B 'type-c':4A,33B 'typec':27B,88C 'unattach':374C 'usb':3A,26B,32B,87C,285C,306C 'usb-rol':305C 'usb-typec':25B 'vbus':12A,41B,74B,141C,149C,212C,214C,217C,233C,259C,263C,265C,279C,330C,333C,349C,352C 'voltage/current':291C 'vsafe0v':334C,353C 'vulner':83C 'wait':322C,361C,371C 'without':190C","nicknames":[],"mitigations":[],"who_affected":"Systems running a Linux kernel with the USB Type-C tcpm driver that includes this change, such as devices with USB-C power delivery ports. The sources do not list affected kernel versions or say which hardware is most exposed.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:17:29+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98761","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98761","severity":null,"published_at":"2026-10-18T16:17:29+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"}