CVE-2021-47450

KVM: arm64: Fix host stage-2 PGD refcount

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().

N/A

CVSS

Severity:

EPSS 0.06%

Affected: Linux Linux

References

Link	Tags
https://git.kernel.org/stable/c/b372264c66ef78f2cab44e877fbd765ad6d24c39
https://git.kernel.org/stable/c/1d58a17ef54599506d44c45ac95be27273a4d2b1

Frequently Asked Questions

What is the severity of CVE-2021-47450?: CVE-2021-47450 has not yet been assigned a CVSS score.
How to fix CVE-2021-47450?: To fix CVE-2021-47450, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-47450 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2021-47450 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-47450?: CVE-2021-47450 affects Linux Linux, Linux Linux.

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