CVE-2021-47450
Medium
Elevated severity or exploit probability.
CVSS base
8.8
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS — probability of exploitation (30 days)
0.2%
11.1th percentile
CISA KEV
Not listed
Weakness / dates
—
Published 2024-05-22 · modified 2026-08-04
CVSS breakdown
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
| Attack Vector | L | Local |
| Attack Complexity | L | Low |
| Privileges Required | L | Low |
| User Interaction | N | None |
| Scope | C | Changed |
| Confidentiality | H | High |
| Integrity | H | High |
| Availability | H | High |
Timeline
- 2024-05-22 — Published (NVD)
- 2026-08-04 — Last modified (NVD)
Description
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Fix host stage-2 PGD refcount The KVM page-table library refcounts the pages of concatenated stage-2 PGDs individually. However, when running KVM in protected mode, the host's stage-2 PGD is currently managed by EL2 as a single high-order compound page, which can cause the refcount of the tail pages to reach 0 when they shouldn't, hence corrupting the page-table. Fix this by introducing a new hyp_split_page() helper in the EL2 page allocator (matching the kernel's split_page() function), and make use of it from host_s2_zalloc_pages_exact().