CVE-2020-15706 GRUB2 contains a race condition leading to a use-after-free vulnerability which can be triggered by redefining a function whilst the same function is already executing.

[
  {
    "product": "grub2 in Ubuntu",
    "vendor": "Ubuntu",
    "versions": [
      {
        "lessThan": "2.04-1ubuntu26.1",
        "status": "affected",
        "version": "20.04 LTS",
        "versionType": "custom"
      },
      {
        "lessThan": "2.02-2ubuntu8.16",
        "status": "affected",
        "version": "18.04 LTS",
        "versionType": "custom"
      },
      {
        "lessThan": "2.02~beta2-36ubuntu3.26",
        "status": "affected",
        "version": "16.04 LTS",
        "versionType": "custom"
      },
      {
        "lessThan": "2.02~beta2-9ubuntu1.20",
        "status": "affected",
        "version": "14.04 ESM",
        "versionType": "custom"
      }
    ]
  }
]