In the Linux kernel, the following vulnerability has been resolved:
KVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory
Ignore nCR3[4:0] when loading PDPTEs from memory for nested SVM, as bits
4:0 of CR3 are ignored when PAE paging is used, and thus VMRUN doesn't
enforce 32-byte alignment of nCR3.
In the absolute worst case scenario, failure to ignore bits 4:0 can result
in an out-of-bounds read, e.g. if the target page is at the end of a
memslot, and the VMM isn't using guard pages.
Per the APM:
The CR3 register points to the base address of the page-directory-pointer
table. The page-directory-pointer table is aligned on a 32-byte boundary,
with the low 5 address bits 4:0 assumed to be 0.
And the SDM's much more explicit:
4:0 Ignored
Note, KVM gets this right when loading PDPTRs, it's only the nSVM flow
that is broken.
Metrics
Affected Vendors & Products
References
History
Thu, 19 Dec 2024 14:45:00 +0000
Type | Values Removed | Values Added |
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First Time appeared |
Redhat
Redhat enterprise Linux |
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CPEs | cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:enterprise_linux:9 |
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Vendors & Products |
Redhat
Redhat enterprise Linux |
Wed, 27 Nov 2024 02:30:00 +0000
Type | Values Removed | Values Added |
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Weaknesses | CWE-125 | |
Metrics |
cvssV3_1
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cvssV3_1
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Fri, 08 Nov 2024 16:15:00 +0000
Type | Values Removed | Values Added |
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References |
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Wed, 06 Nov 2024 13:45:00 +0000
Type | Values Removed | Values Added |
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References |
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Metrics |
threat_severity
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cvssV3_1
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Tue, 05 Nov 2024 17:30:00 +0000
Type | Values Removed | Values Added |
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Description | In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory Ignore nCR3[4:0] when loading PDPTEs from memory for nested SVM, as bits 4:0 of CR3 are ignored when PAE paging is used, and thus VMRUN doesn't enforce 32-byte alignment of nCR3. In the absolute worst case scenario, failure to ignore bits 4:0 can result in an out-of-bounds read, e.g. if the target page is at the end of a memslot, and the VMM isn't using guard pages. Per the APM: The CR3 register points to the base address of the page-directory-pointer table. The page-directory-pointer table is aligned on a 32-byte boundary, with the low 5 address bits 4:0 assumed to be 0. And the SDM's much more explicit: 4:0 Ignored Note, KVM gets this right when loading PDPTRs, it's only the nSVM flow that is broken. | |
Title | KVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory | |
References |
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MITRE
Status: PUBLISHED
Assigner: Linux
Published: 2024-11-05T17:10:46.677Z
Updated: 2024-12-19T09:33:23.812Z
Reserved: 2024-10-21T19:36:19.947Z
Link: CVE-2024-50115
Vulnrichment
No data.
NVD
Status : Undergoing Analysis
Published: 2024-11-05T18:15:14.700
Modified: 2024-11-08T16:15:46.980
Link: CVE-2024-50115
Redhat