{"schemaVersion":3,"id":"USN-4432-2","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"grub2, grub2-signed regression\n\nUSN-4432-1 fixed vulnerabilities in GRUB2 affecting Secure Boot\nenvironments. Unfortunately, the update introduced regressions for\nsome BIOS systems (either pre-UEFI or UEFI configured in Legacy mode),\npreventing them from successfully booting. This update addresses\nthe issue.\n\nUsers with BIOS systems that installed GRUB2 versions from USN-4432-1\nshould verify that their GRUB2 installation has a correct understanding\nof their boot device location and installed the boot loader correctly.\n\nWe apologize for the inconvenience.\n\nOriginal advisory details:\n\n Jesse Michael and Mickey Shkatov discovered that the configuration parser\n in GRUB2 did not properly exit when errors were discovered, resulting in\n heap-based buffer overflows. A local attacker could use this to execute\n arbitrary code and bypass UEFI Secure Boot restrictions. (CVE-2020-10713)\n\n Chris Coulson discovered that the GRUB2 function handling code did not\n properly handle a function being redefined, leading to a use-after-free\n vulnerability. A local attacker could use this to execute arbitrary code\n and bypass UEFI Secure Boot restrictions. (CVE-2020-15706)\n\n Chris Coulson discovered that multiple integer overflows existed in GRUB2\n when handling certain filesystems or font files, leading to heap-based\n buffer overflows. A local attacker could use these to execute arbitrary\n code and bypass UEFI Secure Boot restrictions. (CVE-2020-14309,\n CVE-2020-14310, CVE-2020-14311)\n\n It was discovered that the memory allocator for GRUB2 did not validate\n allocation size, resulting in multiple integer overflows and heap-based\n buffer overflows when handling certain filesystems, PNG images or disk\n metadata. A local attacker could use this to execute arbitrary code and\n bypass UEFI Secure Boot restrictions. (CVE-2020-14308)\n\n Mathieu Trudel-Lapierre discovered that in certain situations, GRUB2\n failed to validate kernel signatures. A local attacker could use this\n to bypass Secure Boot restrictions. (CVE-2020-15705)\n\n Colin Watson and Chris Coulson discovered that an integer overflow\n existed in GRUB2 when handling the initrd command, leading to a heap-based\n buffer overflow. A local attacker could use this to execute arbitrary code\n and bypass UEFI Secure Boot restrictions. (CVE-2020-15707)","dates":{"published":"2020-08-04T23:54:15.000Z","modified":"2026-06-29T13:48:03.309Z","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","name":"grub2","label":"grub2","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/grub2","purlType":"deb","versions":[{"text":"< 2.02~beta2-9ubuntu1.21","noFixRecorded":false,"fixedIn":null},{"text":"< 2.02~beta2-36ubuntu3.27","noFixRecorded":false,"fixedIn":null},{"text":"< 2.02-2ubuntu8.17","noFixRecorded":false,"fixedIn":null},{"text":"< 2.04-1ubuntu26.2","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 2.02~beta2-9ubuntu1.21 | < 2.02~beta2-36ubuntu3.27 | < 2.02-2ubuntu8.17 | < 2.04-1ubuntu26.2","eol":null,"hubHref":null},{"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":"< 1.34.24","noFixRecorded":false,"fixedIn":null},{"text":"< 1.66.27","noFixRecorded":false,"fixedIn":null},{"text":"< 1.93.19","noFixRecorded":false,"fixedIn":null},{"text":"< 1.142.4","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 1.34.24 | < 1.66.27 | < 1.93.19 | < 1.142.4","eol":null,"hubHref":null}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://ubuntu.com/security/notices/USN-4432-2","label":"ubuntu.com/security/notices/USN-4432-2","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://launchpad.net/bugs/1889556","label":"launchpad.net/bugs/1889556","hostname":"launchpad.net","tags":["REPORT"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2020-08-04T23:54:15.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-06-29T13:48:03.309Z","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":"2026-10-20T03:32:14.648Z","stale":false,"partial":false}}