{"id":"CVE-2026-28247","kind":"vulnerability","aliases":["CVE-2026-28247"],"related":[],"title":"AMD SEV firmware: a hypervisor can alter guest page encryption bits","description":"Improper Access Control Applied to Mirrored or Aliased Memory Regions in AMD Secure Encrypted Virtualization (SEV) firmware could allow a malicious hypervisor to change the encryption bit for guest context pages potentially resulting in loss of integrity.","summary":"AMD Secure Encrypted Virtualization firmware has an access control flaw in mirrored or aliased memory regions. A malicious hypervisor can change the encryption bit on guest context pages, which can lead to loss of guest data integrity.","severity":"medium","cvss":5.9,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["amd","hypervisor","infrastructure","sev","virtualization"],"not_affected_if":["no-sev-guests"],"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":"2026-11-10T22:29:20+00:00","updated_at":"2026-11-10T22:29:20+00:00","category":"infrastructure","confidence":0.5,"triage":{"at":"2026-11-10T22:29:20Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"local","title":"AMD SEV firmware: a hypervisor can alter guest page encryption bits","impact":"medium","summary":"AMD Secure Encrypted Virtualization firmware has an access control flaw in mirrored or aliased memory regions. A malicious hypervisor can change the encryption bit on guest context pages, which can lead to loss of guest data integrity.","audience":"businesses","category":"infrastructure","nicknames":[],"who_cares":["amd","sev","hypervisor","virtualization"],"confidence":0.5,"fix_status":"unknown","needs_auth":"unknown","worst_case":"guest pages lose integrity through encryption bit manipulation","analyst_note":"Check AMD's security bulletin for affected firmware versions and fixes; the sources give only the NVD description.","how_to_check":"- unknown","plain_action":"","product_name":"","needs_analyst":true,"not_affected_if":["no-sev-guests"],"who_is_affected":"Affects hosts running AMD EPYC processors with SEV-enabled virtual machines under a hypervisor that could be malicious. Exposure depends on the platform firmware version, which the sources do not name. Hosts without SEV-enabled guests, and teams using managed cloud VMs where the provider handles firmware, can likely skip it, but the sources do not confirm this.","user_interaction":"unknown","product_ecosystem":"","needs_special_setup":"yes","severity_if_unknown":"medium"},"cost_usd":0.000707,"input_tokens":4558,"output_tokens":502,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-2026':13A,16A '-28247':14A,17A 'access':30B,61C 'alias':36B,67C 'allow':78C 'alter':7A 'amd':1A,18B,23B,71C 'appli':63C 'bit':11A,46B,86C 'chang':43B,83C 'context':49B,89C 'control':31B,62C 'could':77C 'cve':12A,15A 'data':58B 'encrypt':10A,25B,45B,73C,85C 'firmwar':3A,27B,76C 'flaw':32B 'guest':8A,48B,57B,88C 'hypervisor':5A,19B,41B,81C 'improp':60C 'infrastructur':20B 'integr':59B,96C 'lead':53B 'loss':55B,94C 'malici':40B,80C 'memori':37B,68C 'mirror':34B,65C 'page':9A,50B,90C 'potenti':91C 'region':38B,69C 'result':92C 'secur':24B,72C 'sev':2A,21B,75C 'virtual':22B,26B,74C","nicknames":[],"mitigations":[],"who_affected":"Affects hosts running AMD EPYC processors with SEV-enabled virtual machines under a hypervisor that could be malicious. Exposure depends on the platform firmware version, which the sources do not name. Hosts without SEV-enabled guests, and teams using managed cloud VMs where the provider handles firmware, can likely skip it, but the sources do not confirm this.","tier":"C","verified":{},"analyst_revisit_at":null,"fix_status":"none","audience":"businesses","plain_action":null,"pkeys":[],"ptokens":[],"labels":["amd","hypervisor","infrastructure","medium","sev","virtualization"],"campaign_type":null,"search_a":"'-2026':13A,16A '-28247':14A,17A 'alter':7A 'amd':1A 'bit':11A 'cve':12A,15A 'encrypt':10A 'firmwar':3A 'guest':8A 'hypervisor':5A 'page':9A 'sev':2A","search_b":"'access':30B 'alias':36B 'amd':18B,23B 'bit':46B 'chang':43B 'context':49B 'control':31B 'data':58B 'encrypt':25B,45B 'firmwar':27B 'flaw':32B 'guest':48B,57B 'hypervisor':19B,41B 'infrastructur':20B 'integr':59B 'lead':53B 'loss':55B 'malici':40B 'memori':37B 'mirror':34B 'page':50B 'region':38B 'secur':24B 'sev':21B 'virtual':22B,26B","search_c":"'access':61C 'alias':67C 'allow':78C 'amd':71C 'appli':63C 'bit':86C 'chang':83C 'context':89C 'control':62C 'could':77C 'encrypt':73C,85C 'firmwar':76C 'guest':88C 'hypervisor':81C 'improp':60C 'integr':96C 'loss':94C 'malici':80C 'memori':68C 'mirror':65C 'page':90C 'potenti':91C 'region':69C 'result':92C 'secur':72C 'sev':75C 'virtual':74C","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: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-2026-28247","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-28247","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"}