{"id":"CVE-2026-98727","kind":"vulnerability","aliases":["CVE-2026-98727"],"related":[],"title":"Linux kernel NVMe multipath: zoned devices can crash on zero zone size","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvme-multipath: set BLK_FEAT_ZONED only after the zone info is known\n\nThe namespace head is marked zoned at allocation time based only on the\ncommand set identifier.  If the zone info query reports a zero zone size,\nthe path namespace is registered without zoned limits while the head\nstill advertises the zoned capability with a zone size of zero, and\nreporting zones or writing to the head then shifts by ilog2(0).\n\nDrop the zoned feature from the head allocation and let the head limits\nrefresh stack it in from the path namespace instead.","summary":"In the Linux NVMe multipath code, the namespace head is marked zoned before the zone size is known, so a zero zone size can be registered on the path while the head still advertises zoned support. Reporting zones or writing to the head then shifts by ilog2(0), which the sources do not say leads to more than a fault or crash.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","kernel","linux","nvme","storage"],"not_affected_if":["no-nvme-multipath","no-zoned-nvme"],"how_to_check":"- `uname -r` to get the running kernel version\n- `lsblk -o NAME,ZONED` to see whether any NVMe namespace reports a zoned model\n- unknown for the exact fixed kernel version","fix":"- Update the Linux kernel to a release that includes the upstream nvme-multipath fix; the fixed version numbers are unknown from the sources\n- Reboot into the updated kernel after installing it","status":"open","published_at":"2026-10-18T16:17:26+00:00","first_seen_at":"2026-10-23T21:57:16+00:00","triaged_at":"2026-10-25T05:17:18+00:00","updated_at":"2026-10-25T05:17:18+00:00","category":"infrastructure","confidence":0.4,"triage":{"at":"2026-10-25T05:17:18Z","model":"claude-haiku-5-5","output":{"fix":"- Update the Linux kernel to a release that includes the upstream nvme-multipath fix; the fixed version numbers are unknown from the sources\n- Reboot into the updated kernel after installing it","reach":"local","title":"Linux kernel NVMe multipath: zoned devices can crash on zero zone size","impact":"low","summary":"In the Linux NVMe multipath code, the namespace head is marked zoned before the zone size is known, so a zero zone size can be registered on the path while the head still advertises zoned support. Reporting zones or writing to the head then shifts by ilog2(0), which the sources do not say leads to more than a fault or crash.","category":"infrastructure","nicknames":[],"who_cares":["linux","nvme","storage","kernel"],"confidence":0.4,"needs_auth":"unknown","worst_case":"unknown; the sources only say the shift by ilog2(0) occurs","analyst_note":"Check the NVD entry and the upstream kernel commit for the fixed kernel versions and the real impact of the ilog2(0) shift.","how_to_check":"- `uname -r` to get the running kernel version\n- `lsblk -o NAME,ZONED` to see whether any NVMe namespace reports a zoned model\n- unknown for the exact fixed kernel version","needs_analyst":true,"not_affected_if":["no-zoned-nvme","no-nvme-multipath"],"who_is_affected":"Only systems that use NVMe zoned namespaces behind nvme-multipath, where the zone info query reports a zero zone size. Hosts with no zoned NVMe namespaces have no exposure to this path. The sources do not say whether an attacker can trigger it remotely.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.00065,"input_tokens":3418,"output_tokens":617,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-2026':14A,17A '-98727':15A,18A '0':71B,170C 'advertis':57B,148C 'alloc':117C,178C 'base':119C 'blk':100C 'capabl':151C 'code':29B 'command':123C 'crash':8A,85B 'cve':13A,16A 'devic':6A 'drop':171C 'fault':83B 'feat':101C 'featur':174C 'follow':91C 'head':32B,55B,66B,112C,146C,165C,177C,182C 'identifi':125C 'ilog2':70B,169C 'info':107C,129C 'infrastructur':19B 'instead':192C 'kernel':2A,20B,89C 'known':41B,109C 'lead':78B 'let':180C 'limit':143C,183C 'linux':1A,21B,26B,88C 'mark':34B,114C 'multipath':4A,28B,98C 'namespac':31B,111C,138C,191C 'nvme':3A,22B,27B,97C 'nvme-multipath':96C 'path':52B,137C,190C 'queri':130C 'refresh':184C 'regist':49B,140C 'report':60B,131C,159C 'resolv':95C 'say':77B 'set':99C,124C 'shift':68B,167C 'size':12A,39B,46B,135C,155C 'sourc':74B 'stack':185C 'still':56B,147C 'storag':23B 'support':59B 'time':118C 'vulner':92C 'without':141C 'write':63B,162C 'zero':10A,44B,133C,157C 'zone':5A,11A,35B,38B,45B,58B,61B,102C,106C,115C,128C,134C,142C,150C,154C,160C,173C","nicknames":[],"mitigations":[],"who_affected":"Only systems that use NVMe zoned namespaces behind nvme-multipath, where the zone info query reports a zero zone size. Hosts with no zoned NVMe namespaces have no exposure to this path. The sources do not say whether an attacker can trigger it remotely.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:17:26+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98727","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98727","severity":null,"published_at":"2026-10-18T16:17:26+00:00","modified_at":"2026-10-19T10:19:36+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"}