{"id":"CVE-2026-98450","kind":"vulnerability","aliases":["CVE-2026-98450"],"related":[],"title":"Linux kernel SMB client: failed compound requests can leave remote file handles open","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: close completed creates on compound wait errors\n\ncompound_send_recv() waits for responses in order. If a later wait is\ninterrupted, or if a later MID fails during response synchronization, an\nearlier CREATE may already have opened a remote handle. The earlier mid\nis then released without invoking handle_cancelled_mid(), leaving the\nremote handle open because no FID was copied to the caller.\n\nMark completed earlier mids as cancelled when a compound wait or MID\nsynchronization aborts. Keep their response buffers attached while the\nMIDs are synchronized, and transfer them only after synchronization of\nthe processed responses, so the release path can inspect successful\nCREATE responses and queue SMB2_close() after a later failure. Account for\na remote open only after the close work is allocated and before it is\nqueued, since the caller has not yet updated num_remote_opens. Mark the\ncreate+close compound used by smb2_unlink() so it is not closed again.\nNon-CREATE responses and compounds that already include a close keep their\nexisting behavior.","summary":"When a compound SMB request is interrupted or a later response fails, an earlier CREATE may have opened a remote file handle that the kernel never closes. An attacker who can reach a malicious or compromised SMB server can make the client leak server-side handles.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["cifs","infrastructure","kernel","linux","self-hosted","smb"],"not_affected_if":["no-smb-mounts"],"how_to_check":"- Check the running kernel version with `uname -r` and compare it against the fixed kernel release in the NVD record\n- Check whether the SMB client module is loaded with `lsmod | grep cifs`","fix":"- Update the Linux kernel to a release that includes the upstream fix for CVE-2026-98450 (fixed version unknown from the sources)","status":"open","published_at":"2026-10-18T16:16:55+00:00","first_seen_at":"2026-10-23T21:57:15+00:00","triaged_at":"2026-10-25T05:27:25+00:00","updated_at":"2026-10-25T05:27:25+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-10-25T05:27:25Z","model":"claude-haiku-5-5","output":{"fix":"- Update the Linux kernel to a release that includes the upstream fix for CVE-2026-98450 (fixed version unknown from the sources)","reach":"network","title":"Linux kernel SMB client: failed compound requests can leave remote file handles open","impact":"low","summary":"When a compound SMB request is interrupted or a later response fails, an earlier CREATE may have opened a remote file handle that the kernel never closes. An attacker who can reach a malicious or compromised SMB server can make the client leak server-side handles.","category":"infrastructure","nicknames":[],"who_cares":["linux","kernel","smb","cifs","self-hosted"],"confidence":0.5,"needs_auth":"unknown","worst_case":"remote file handles stay open on the SMB server","analyst_note":"Find the fixed kernel version and stable backport commits in the NVD record or the kernel stable git log for this CVE.","how_to_check":"- Check the running kernel version with `uname -r` and compare it against the fixed kernel release in the NVD record\n- Check whether the SMB client module is loaded with `lsmod | grep cifs`","needs_analyst":true,"not_affected_if":["no-smb-mounts"],"who_is_affected":"Systems that mount SMB/CIFS shares with the Linux kernel cifs client are exposed. Systems that do not mount SMB shares, or that use only other filesystems, can skip it.","user_interaction":"unknown","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000619,"input_tokens":3569,"output_tokens":524,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-98450':16A,19A 'abort':164C 'account':202C 'alloc':213C 'alreadi':121C,251C 'attach':169C 'attack':56B 'behavior':258C 'buffer':168C 'caller':150C,221C 'cancel':136C,156C 'cif':20B 'client':4A,69B,86C 'close':54B,87C,197C,210C,232C,242C,254C 'complet':88C,152C 'compound':6A,30B,91C,94C,159C,233C,249C 'compromis':63B 'copi':147C 'creat':42B,89C,119C,192C,231C,246C 'cve':14A,17A 'earlier':41B,118C,128C,153C 'error':93C 'exist':257C 'fail':5A,39B,113C 'failur':201C 'fid':145C 'file':11A,48B 'follow':80C 'handl':12A,49B,74B,126C,135C,141C 'host':26B 'includ':252C 'infrastructur':21B 'inspect':190C 'interrupt':34B,107C 'invok':134C 'keep':165C,255C 'kernel':2A,22B,52B,78C 'later':37B,104C,111C,200C 'leak':70B 'leav':9A,138C 'linux':1A,23B,77C 'make':67B 'malici':61B 'mark':151C,229C 'may':43B,120C 'mid':112C,129C,137C,154C,162C,172C 'never':53B 'non':245C 'non-creat':244C 'num':226C 'open':13A,45B,123C,142C,206C,228C 'order':101C 'path':188C 'process':183C 'queu':218C 'queue':195C 'reach':59B 'recv':96C 'releas':132C,187C 'remot':10A,47B,125C,140C,205C,227C 'request':7A,32B 'resolv':84C 'respons':38B,99C,115C,167C,184C,193C,247C 'self':25B 'self-host':24B 'send':95C 'server':65B,72B 'server-sid':71B 'side':73B 'sinc':219C 'smb':3A,27B,31B,64B,85C 'smb2':196C,236C 'success':191C 'synchron':116C,163C,174C,180C 'transfer':176C 'unlink':237C 'updat':225C 'use':234C 'vulner':81C 'wait':92C,97C,105C,160C 'without':133C 'work':211C 'yet':224C","nicknames":[],"mitigations":[],"who_affected":"Systems that mount SMB/CIFS shares with the Linux kernel cifs client are exposed. Systems that do not mount SMB shares, or that use only other filesystems, can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:16:55+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98450","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98450","severity":null,"published_at":"2026-10-18T16:16:55+00:00","modified_at":"2026-10-21T13:21:30+00:00","first_seen_at":"2026-10-23T21:57:15+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"}