{"schemaVersion":3,"id":"USN-5091-3","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"linux-azure, linux-azure-5.4 regression\n\nUSN-5091-1 fixed vulnerabilities in Linux 5.4-based kernels.\nUnfortunately, for Linux kernels intended for use within Microsoft\nAzure environments, that update introduced a regression that could\ncause the kernel to fail to boot in large Azure instance types.\nThis update fixes the problem.\n\nWe apologize for the inconvenience.\n\nOriginal advisory details:\n\n Ofek Kirzner, Adam Morrison, Benedict Schlueter, and Piotr Krysiuk\n discovered that the BPF verifier in the Linux kernel missed possible\n mispredicted branches due to type confusion, allowing a side-channel\n attack. An attacker could use this to expose sensitive information.\n (CVE-2021-33624)\n\n It was discovered that the tracing subsystem in the Linux kernel did not\n properly keep track of per-cpu ring buffer state. A privileged attacker\n could use this to cause a denial of service. (CVE-2021-3679)\n\n Alexey Kardashevskiy discovered that the KVM implementation for PowerPC\n systems in the Linux kernel did not properly validate RTAS arguments in\n some situations. An attacker in a guest vm could use this to cause a denial\n of service (host OS crash) or possibly execute arbitrary code.\n (CVE-2021-37576)\n\n It was discovered that the Virtio console implementation in the Linux\n kernel did not properly validate input lengths in some situations. A local\n attacker could possibly use this to cause a denial of service (system\n crash). (CVE-2021-38160)\n\n Michael Wakabayashi discovered that the NFSv4 client implementation in the\n Linux kernel did not properly order connection setup operations. An\n attacker controlling a remote NFS server could use this to cause a denial\n of service on the client. (CVE-2021-38199)\n\n It was discovered that the MAX-3421 host USB device driver in the Linux\n kernel did not properly handle device removal events. A physically\n proximate attacker could use this to cause a denial of service (system\n crash). (CVE-2021-38204)","dates":{"published":"2021-10-15T00:11:45.000Z","modified":"2026-02-10T04:42:19.000Z","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":"linux-azure","name":"linux-azure","label":"linux-azure","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/linux-azure","purlType":"deb","versions":[{"text":"< 5.4.0-1061.64","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 5.4.0-1061.64","eol":null,"hubHref":null},{"vendor":"ubuntu","product":"linux-azure-5.4","name":"linux-azure-5.4","label":"linux-azure-5.4","ecosystem":"Ubuntu","cpePart":null,"purl":"pkg:deb/ubuntu/linux-azure-5.4","purlType":"deb","versions":[{"text":"< 5.4.0-1061.64~18.04.1","noFixRecorded":false,"fixedIn":null}],"versionsText":"< 5.4.0-1061.64~18.04.1","eol":null,"hubHref":null}],"affectedCount":2,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://ubuntu.com/security/notices/USN-5091-3","label":"ubuntu.com/security/notices/USN-5091-3","hostname":"ubuntu.com","tags":["Advisory"]},{"url":"https://launchpad.net/bugs/1940564","label":"launchpad.net/bugs/1940564","hostname":"launchpad.net","tags":["REPORT"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2021-10-15T00:11:45.000Z","label":"Published","detail":"Vulnerability first disclosed.","source":null},{"kind":"modified","date":"2026-02-10T04:42:19.000Z","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":"2026-10-19T19:07:00.240Z","stale":false,"partial":false}}