{"id":"CVE-2026-102704","kind":"vulnerability","aliases":["CVE-2026-102704"],"related":[],"title":"Xen: grant copy check lets a guest copy another domain's memory","description":"[This CNA information record relates to multiple CVEs; the\ntext explains which aspects/vulnerabilities correspond to which CVE.]\n\nA common access pattern is a batch of Grant Copy operations acting on\nadjacent address ranges in the same source or destination page.  For\nperformance reasons, Xen caches details internally to reuse already\nvalidated data.  The conditions on when to re-validate the internal data\nwere not correct in some cases:\n\n - Frame numbers and grant references could wrongly be mixed up.  This\n   is CVE-2026-102703.\n\n - Copying by frame number (rather than grant reference) is permitted\n   only when operating on the caller's own memory.  The check to enforce\n   this restriction was misplaced.  This is CVE-2026-102704.","summary":"Xen caches validation data across batches of grant copy operations, and the check that restricts copying by frame number to a caller's own memory is misplaced. A guest may be able to copy memory belonging to other domains, which can expose data across virtual machine boundaries.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["hypervisor","infrastructure","self-hosted","virtualization","xen"],"not_affected_if":[],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-04T11:17:07+00:00","first_seen_at":"2026-11-04T11:26:45+00:00","triaged_at":"2026-11-04T11:27:48+00:00","updated_at":"2026-11-04T11:27:48+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-04T11:27:48Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"Xen: grant copy check lets a guest copy another domain's memory","impact":"high","summary":"Xen caches validation data across batches of grant copy operations, and the check that restricts copying by frame number to a caller's own memory is misplaced. A guest may be able to copy memory belonging to other domains, which can expose data across virtual machine boundaries.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["xen","hypervisor","self-hosted","virtualization"],"confidence":0.5,"fix_status":"unknown","needs_auth":"yes","worst_case":"guest reads or writes memory of other domains","analyst_note":"Find the affected Xen version ranges and fixed versions in the Xen security advisory referenced by the NVD record.","how_to_check":"- unknown","plain_action":"","needs_analyst":true,"not_affected_if":[],"who_is_affected":"Affects Xen hypervisor hosts that run guest virtual machines using grant table copy operations. The sources do not state which Xen versions are affected or which configurations are exposed. Systems not running Xen can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"unknown"},"cost_usd":0.000645,"input_tokens":4267,"output_tokens":437,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-102703':156C '-102704':15A,18A,188C '-2026':14A,17A,155C,187C 'abl':57B 'access':92C 'across':30B,69B 'act':101C 'address':104C 'adjac':103C 'alreadi':122C 'anoth':9A 'aspects/vulnerabilities':85C 'batch':31B,96C 'belong':61B 'boundari':72B 'cach':27B,117C 'caller':47B,172C 'case':141C 'check':4A,38B,177C 'cna':74C 'common':91C 'condit':126C 'copi':3A,8A,34B,41B,59B,99C,157C 'correct':138C 'correspond':86C 'could':147C 'cve':13A,16A,89C,154C,186C 'cves':80C 'data':29B,68B,124C,135C 'destin':111C 'detail':118C 'domain':10A,64B 'enforc':179C 'explain':83C 'expos':67B 'frame':43B,142C,159C 'grant':2A,33B,98C,145C,163C 'guest':7A,54B 'host':23B 'hypervisor':19B 'inform':75C 'infrastructur':20B 'intern':119C,134C 'let':5A 'machin':71B 'may':55B 'memori':12A,50B,60B,175C 'misplac':52B,183C 'mix':150C 'multipl':79C 'number':44B,143C,160C 'oper':35B,100C,169C 'page':112C 'pattern':93C 'perform':114C 'permit':166C 'rang':105C 'rather':161C 're':131C 're-valid':130C 'reason':115C 'record':76C 'refer':146C,164C 'relat':77C 'restrict':40B,181C 'reus':121C 'self':22B 'self-host':21B 'sourc':109C 'text':82C 'valid':28B,123C,132C 'virtual':24B,70B 'wrong':148C 'xen':1A,25B,26B,116C","nicknames":[],"mitigations":[],"who_affected":"Affects Xen hypervisor hosts that run guest virtual machines using grant table copy operations. The sources do not state which Xen versions are affected or which configurations are exposed. Systems not running Xen can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["hypervisor","infrastructure","selfhosted","unknown","virtualization","xen"],"campaign_type":null,"first_public_at":"2026-11-04T11:17:07+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-102704","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-102704","severity":null,"published_at":"2026-11-04T11:17:07+00:00","modified_at":"2026-11-04T11:17:07+00:00","first_seen_at":"2026-11-04T11:26:45+00:00","fetched_at":"2026-11-04T11:26:45+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"}