{"id":"CVE-2026-40670","kind":"vulnerability","aliases":["CVE-2026-40670"],"related":[],"title":"AMD SEV-SNP: privileged attacker can overlap MMIO and DRAM regions","description":"Improper check for unusual or exceptional conditions in AMD Secure Encrypted Virtualization - Secure Nested Paging (SEV-SNP) could allow a privileged attacker to potentially overlap MMIO regions with DRAM regions resulting in loss of integrity.","summary":"AMD Secure Encrypted Virtualization with Secure Nested Paging (SEV-SNP) fails to check for unusual conditions, so a privileged attacker can map MMIO regions over DRAM regions. The result is loss of data integrity for protected virtual machines.","severity":"medium","cvss":5.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["amd","confidential-computing","hypervisor","infrastructure","sev-snp"],"not_affected_if":["no-sev-snp","non-amd-hardware"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T22:18:33+00:00","first_seen_at":"2026-11-10T22:27:30+00:00","triaged_at":"2026-11-10T22:29:19+00:00","updated_at":"2026-11-10T22:29:19+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-10T22:29:19Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"AMD SEV-SNP: privileged attacker can overlap MMIO and DRAM regions","impact":"medium","summary":"AMD Secure Encrypted Virtualization with Secure Nested Paging (SEV-SNP) fails to check for unusual conditions, so a privileged attacker can map MMIO regions over DRAM regions. The result is loss of data integrity for protected virtual machines.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["amd","sev-snp","confidential-computing","hypervisor"],"confidence":0.5,"fix_status":"unknown","needs_auth":"yes","worst_case":"Memory integrity of confidential VMs is lost on the host","analyst_note":"Check the AMD security bulletin and the NVD entry for affected processor families and fixed firmware or microcode versions.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-sev-snp","non-amd-hardware"],"who_is_affected":"Affects hosts running AMD EPYC processors with SEV-SNP enabled for confidential virtual machines. The attacker needs privileged access on the host, so ordinary guests and internet users are not the main concern. Teams without SEV-SNP confidential computing can skip it.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000706,"input_tokens":4553,"output_tokens":501,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':14A,17A '-40670':15A,18A 'allow':86C 'amd':1A,19B,28B,75C 'attack':6A,48B,89C 'check':41B,68C 'comput':22B 'condit':44B,73C 'confidenti':21B 'confidential-comput':20B 'could':85C 'cve':13A,16A 'data':61B 'dram':11A,54B,96C 'encrypt':30B,77C 'except':72C 'fail':39B 'hypervisor':23B 'improp':67C 'infrastructur':24B 'integr':62B,102C 'loss':59B,100C 'machin':66B 'map':50B 'mmio':9A,51B,93C 'nest':34B,80C 'overlap':8A,92C 'page':35B,81C 'potenti':91C 'privileg':5A,47B,88C 'protect':64B 'region':12A,52B,55B,94C,97C 'result':57B,98C 'secur':29B,33B,76C,79C 'sev':3A,26B,37B,83C 'sev-snp':2A,25B,36B,82C 'snp':4A,27B,38B,84C 'unusu':43B,70C 'virtual':31B,65B,78C","nicknames":[],"mitigations":[],"who_affected":"Affects hosts running AMD EPYC processors with SEV-SNP enabled for confidential virtual machines. The attacker needs privileged access on the host, so ordinary guests and internet users are not the main concern. Teams without SEV-SNP confidential computing can skip it.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["amd","confidentialcomputing","hypervisor","infrastructure","medium","sevsnp"],"campaign_type":null,"search_a":"'-2026':14A,17A '-40670':15A,18A 'amd':1A 'attack':6A 'cve':13A,16A 'dram':11A 'mmio':9A 'overlap':8A 'privileg':5A 'region':12A 'sev':3A 'sev-snp':2A 'snp':4A","search_b":"'amd':19B,28B 'attack':48B 'check':41B 'comput':22B 'condit':44B 'confidenti':21B 'confidential-comput':20B 'data':61B 'dram':54B 'encrypt':30B 'fail':39B 'hypervisor':23B 'infrastructur':24B 'integr':62B 'loss':59B 'machin':66B 'map':50B 'mmio':51B 'nest':34B 'page':35B 'privileg':47B 'protect':64B 'region':52B,55B 'result':57B 'secur':29B,33B 'sev':26B,37B 'sev-snp':25B,36B 'snp':27B,38B 'unusu':43B 'virtual':31B,65B","search_c":"'allow':86C 'amd':75C 'attack':89C 'check':68C 'condit':73C 'could':85C 'dram':96C 'encrypt':77C 'except':72C 'improp':67C 'integr':102C 'loss':100C 'mmio':93C 'nest':80C 'overlap':92C 'page':81C 'potenti':91C 'privileg':88C 'region':94C,97C 'result':98C 'secur':76C,79C 'sev':83C 'sev-snp':82C 'snp':84C 'unusu':70C 'virtual':78C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T22:18:33+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:N/SC:N/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"psirt@amd.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-40670","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40670","severity":null,"published_at":"2026-11-10T22:18:33+00:00","modified_at":"2026-11-10T22:18:33+00:00","first_seen_at":"2026-11-10T22:27:30+00:00","fetched_at":"2026-11-10T22:27:30+00:00","note":null}],"documents":[],"disclosures":[],"exploit_sources":[],"notice":"Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai"}