CVE-2021-47450 (GCVE-0-2021-47450)

Vulnerability from cvelistv5 – Published: 2024-05-22 06:19 – Updated: 2025-05-04 07:11
VLAI?
Title
KVM: arm64: Fix host stage-2 PGD refcount
Summary
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().
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1025c8c0c6accfcbdc8f52ca1940160f65cd87d6 , < b372264c66ef78f2cab44e877fbd765ad6d24c39 (git)
Affected: 1025c8c0c6accfcbdc8f52ca1940160f65cd87d6 , < 1d58a17ef54599506d44c45ac95be27273a4d2b1 (git)
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    Linux Linux Affected: 5.13
Unaffected: 0 , < 5.13 (semver)
Unaffected: 5.14.15 , ≤ 5.14.* (semver)
Unaffected: 5.15 , ≤ * (original_commit_for_fix)
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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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