{"id":"CVE-2026-40668","kind":"vulnerability","aliases":["CVE-2026-40668"],"related":[],"title":"AMD SEV firmware: spoofed requests let a hypervisor fetch VMPL 0 attestation reports","description":"Authentication bypass by spoofing in AMD Secure Encrypted Virtualization (SEV) firmware could allow a malicious hypervisor to request attestation reports for VMPL 0.","summary":"AMD Secure Encrypted Virtualization (SEV) firmware has an authentication bypass by spoofing. A malicious hypervisor can use it to request attestation reports for VMPL 0, the most privileged level inside a confidential virtual machine.","severity":"medium","cvss":4.6,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["amd","confidential-computing","hypervisor","infrastructure","sev"],"not_affected_if":["no-amd-sev"],"how_to_check":null,"fix":null,"status":"open","published_at":"2026-11-10T22:18:32+00:00","first_seen_at":"2026-11-10T22:27:30+00:00","triaged_at":"2026-11-10T22:30:59+00:00","updated_at":"2026-11-10T22:30:59+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-10T22:30:59Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"AMD SEV firmware: spoofed requests let a hypervisor fetch VMPL 0 attestation reports","impact":"medium","summary":"AMD Secure Encrypted Virtualization (SEV) firmware has an authentication bypass by spoofing. A malicious hypervisor can use it to request attestation reports for VMPL 0, the most privileged level inside a confidential virtual machine.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["amd","sev","confidential-computing","hypervisor"],"confidence":0.5,"fix_status":"unknown","needs_auth":"unknown","worst_case":"hypervisor obtains attestation reports for the most privileged VM level","analyst_note":"Find AMD's security bulletin for CVE-2026-40668 to list affected SEV firmware versions and the fixed firmware.","how_to_check":"unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-amd-sev"],"who_is_affected":"Teams running AMD SEV confidential virtual machines, where the hypervisor is the untrusted party. The sources do not name affected firmware versions or products, so unknown.","user_interaction":"no","product_ecosystem":"","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000683,"input_tokens":4525,"output_tokens":461,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':15A,18A '-40668':16A,19A '0':11A,51B,83C 'allow':73C 'amd':1A,20B,27B,66C 'attest':12A,47B,79C 'authent':35B,61C 'bypass':36B,62C 'comput':23B 'confidenti':22B,58B 'confidential-comput':21B 'could':72C 'cve':14A,17A 'encrypt':29B,68C 'fetch':9A 'firmwar':3A,32B,71C 'hypervisor':8A,24B,41B,76C 'infrastructur':25B 'insid':56B 'let':6A 'level':55B 'machin':60B 'malici':40B,75C 'privileg':54B 'report':13A,48B,80C 'request':5A,46B,78C 'secur':28B,67C 'sev':2A,26B,31B,70C 'spoof':4A,38B,64C 'use':43B 'virtual':30B,59B,69C 'vmpl':10A,50B,82C","nicknames":[],"mitigations":[],"who_affected":"Teams running AMD SEV confidential virtual machines, where the hypervisor is the untrusted party. The sources do not name affected firmware versions or products, so unknown.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["amd","confidentialcomputing","hypervisor","infrastructure","medium","sev"],"campaign_type":null,"search_a":"'-2026':15A,18A '-40668':16A,19A '0':11A 'amd':1A 'attest':12A 'cve':14A,17A 'fetch':9A 'firmwar':3A 'hypervisor':8A 'let':6A 'report':13A 'request':5A 'sev':2A 'spoof':4A 'vmpl':10A","search_b":"'0':51B 'amd':20B,27B 'attest':47B 'authent':35B 'bypass':36B 'comput':23B 'confidenti':22B,58B 'confidential-comput':21B 'encrypt':29B 'firmwar':32B 'hypervisor':24B,41B 'infrastructur':25B 'insid':56B 'level':55B 'machin':60B 'malici':40B 'privileg':54B 'report':48B 'request':46B 'secur':28B 'sev':26B,31B 'spoof':38B 'use':43B 'virtual':30B,59B 'vmpl':50B","search_c":"'0':83C 'allow':73C 'amd':66C 'attest':79C 'authent':61C 'bypass':62C 'could':72C 'encrypt':68C 'firmwar':71C 'hypervisor':76C 'malici':75C 'report':80C 'request':78C 'secur':67C 'sev':70C 'spoof':64C 'virtual':69C 'vmpl':82C","cause_entry":null,"cause_path":null,"disclosures_checked_at":null,"first_public_at":"2026-11-10T22:18:32+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:L/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-2026-40668","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40668","severity":null,"published_at":"2026-11-10T22:18:32+00:00","modified_at":"2026-11-10T22:18:32+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"}