{"schemaVersion":3,"id":"USN-4992-1","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"grub2-signed, grub2-unsigned vulnerabilities\n\nMáté Kukri discovered that the acpi command in GRUB 2 allowed privileged\nusers to load crafted ACPI tables when secure boot is enabled. An attacker\ncould use this to bypass UEFI Secure Boot restrictions. (CVE-2020-14372)\n\nChris Coulson discovered that the rmmod command in GRUB 2 contained a use-\nafter-free vulnerability. A local attacker could use this to execute\narbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2020-25632)\n\nChris Coulson discovered that a buffer overflow existed in the command line\nparser in GRUB 2. A local attacker could use this to execute arbitrary code\nand bypass UEFI Secure Boot restrictions. (CVE-2020-27749)\n\nIt was discovered that the cutmem command in GRUB 2 did not honor secure\nboot locking. A local attacker could use this to execute arbitrary code and\nbypass UEFI Secure Boot restrictions. (CVE-2020-27779)\n\nIt was discovered that the option parser in GRUB 2 contained a heap\noverflow vulnerability. A local attacker could use this to execute\narbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2021-20225)\n\nIt was discovered that the menu rendering implementation in GRUB 2 did not\nproperly calculate the amount of memory needed in some situations, leading\nto out-of-bounds writes. A local attacker could use this to execute\narbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2021-20233)","dates":{"published":"2021-06-18T03:57:46.000Z","modified":"2026-04-27T15:54:21.743Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":null,"severity":"unknown","version":null,"versionLabel":null,"source":null,"vector":null,"computed":false,"selection":"none"},"metrics":[]},"epss":{"probability":null,"percentile":null,"severity":"unknown","asOf":null,"change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[],"last30":[]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[],"affected":[{"vendor":"ubuntu","product":"grub2-signed","name":"grub2-signed","label":"grub2-signed","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/grub2-signed","purlType":"deb","versions":[{"text":"< 1.167~18.04.5","noFixRecorded":false,"fixedIn":null},{"text":"< 1.167.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.167~18.04.5 | < 1.167.2","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"grub2-unsigned","name":"grub2-unsigned","label":"grub2-unsigned","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/grub2-unsigned","purlType":"deb","versions":[{"text":"< 2.04-1ubuntu44.1.2","noFixRecorded":false,"fixedIn":null},{"text":"< 2.04-1ubuntu44.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 2.04-1ubuntu44.1.2 | < 2.04-1ubuntu44.2","eol":null,"hubHref":null}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://ubuntu.com/security/notices/USN-4992-1","label":"ubuntu.com/security/notices/USN-4992-1","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://ubuntu.com/security/CVE-2020-14372","label":"ubuntu.com/security/CVE-2020-14372","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2020-25632","label":"ubuntu.com/security/CVE-2020-25632","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2020-27749","label":"ubuntu.com/security/CVE-2020-27749","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2020-27779","label":"ubuntu.com/security/CVE-2020-27779","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2021-20225","label":"ubuntu.com/security/CVE-2021-20225","hostname":"ubuntu.com","tags":["REPORT"]},{"url":"https://ubuntu.com/security/CVE-2021-20233","label":"ubuntu.com/security/CVE-2021-20233","hostname":"ubuntu.com","tags":["REPORT"]}],"lineage":{"upstream":["CVE-2020-14372","CVE-2020-25632","CVE-2020-27749","CVE-2020-27779","CVE-2021-20225","CVE-2021-20233"],"downstream":[],"duplicates":[],"related":["CVE-2020-14372","CVE-2020-25632","CVE-2020-27749","CVE-2020-27779","CVE-2021-20225","CVE-2021-20233"]},"timeline":[{"kind":"published","date":"2021-06-18T03:57:46.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-04-27T15:54:21.743Z","label":"Last modified","detail":"Vulnerability information updated.","source":null}],"risk":{"score":0,"level":"minimal","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-20T04:10:31.716Z","stale":false,"partial":false}}