CVE-2024-50017
In the Linux kernel, the following vulnerability has been resolved: x86/mm/ident_map: Use gbpages only where full GB page should be mapped.
Does this matter?
Lower severity and a low EPSS score (0.22%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: x86/mm/ident_map: Use gbpages only where full GB page should be mapped. When ident_pud_init() uses only GB pages to create identity maps, large ranges of addresses not actually requested can be included in the resulting table; a 4K request will map a full GB. This can include a lot of extra address space past that requested, including areas marked reserved by the BIOS. That allows processor speculation into reserved regions, that on UV systems can cause system halts. Only use GB pages when map creation requests include the full GB page of space. Fall back to using smaller 2M pages when only portions of a GB page are included in the request. No attempt is made to coalesce mapping requests. If a request requires a map entry at the 2M (pmd) level, subsequent mapping requests within the same 1G region will also be at the pmd level, even if adjacent or overlapping such requests could have been combined to map a full GB page. Existing usage starts with larger regions and then adds smaller regions, so this should not have any great consequence.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.22% probability · 13th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/a23823098ab2c277c14fc110b97d8d5c83597195Patch
- https://git.kernel.org/stable/c/cc31744a294584a36bf764a0ffa3255a8e69f036Patch
- https://git.kernel.org/stable/c/d113f9723f2bfd9c6feeb899b8ddbee6b8a6e01f
- https://git.kernel.org/stable/c/d80a99892f7a992d103138fa4636b2c33abd6740Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.