{"cve":"CVE-2021-47228","nvd":{"published":"2024-05-21T15:15:12.250","modified":"2026-06-17T04:16:57.300","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/ioremap: Map EFI-reserved memory as encrypted for SEV\n\nSome drivers require memory that is marked as EFI boot services\ndata. In order for this memory to not be re-used by the kernel\nafter ExitBootServices(), efi_mem_reserve() is used to preserve it\nby inserting a new EFI memory descriptor and marking it with the\nEFI_MEMORY_RUNTIME attribute.\n\nUnder SEV, memory marked with the EFI_MEMORY_RUNTIME attribute needs to\nbe mapped encrypted by Linux, otherwise the kernel might crash at boot\nlike below:\n\n  EFI Variables Facility v0.08 2004-May-17\n  general protection fault, probably for non-canonical address 0x3597688770a868b2: 0000 [#1] SMP NOPTI\n  CPU: 13 PID: 1 Comm: swapper/0 Not tainted 5.12.4-2-default #1 openSUSE Tumbleweed\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n  RIP: 0010:efi_mokvar_entry_next\n  [...]\n  Call Trace:\n   efi_mokvar_sysfs_init\n   ? efi_mokvar_table_init\n   do_one_initcall\n   ? __kmalloc\n   kernel_init_freeable\n   ? rest_init\n   kernel_init\n   ret_from_fork\n\nExpand the __ioremap_check_other() function to additionally check for\nthis other type of boot data reserved at runtime and indicate that it\nshould be mapped encrypted for an SEV guest.\n\n [ bp: Massage commit message. ]","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":6.2},"cwes":[],"references":["https://git.kernel.org/stable/c/208bb686e7fa7fff16e8fa78ff0db34aa9acdbd7","https://git.kernel.org/stable/c/8d651ee9c71bb12fc0c8eb2786b66cbe5aa3e43b","https://git.kernel.org/stable/c/b7a05aba39f733ec337c5b952e112dd2dc4fc404","https://git.kernel.org/stable/c/208bb686e7fa7fff16e8fa78ff0db34aa9acdbd7","https://git.kernel.org/stable/c/8d651ee9c71bb12fc0c8eb2786b66cbe5aa3e43b"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:50:30.954589733+00:00"},"epss":{"cve":"CVE-2021-47228","score":0.00237,"percentile":0.14804,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}