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
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
Wed, 01 Oct 2025 21:30:00 +0000
Type | Values Removed | Values Added |
---|---|---|
First Time appeared |
Linux
Linux linux Kernel |
|
CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.12:rc4:*:*:*:*:*:* |
|
Vendors & Products |
Linux
Linux linux Kernel |
Wed, 01 Oct 2025 21:15:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Metrics |
cvssV3_1
|
ssvc
|
Wed, 16 Jul 2025 13:45:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Metrics |
epss
|
epss
|
Fri, 11 Jul 2025 13:45:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Metrics |
epss
|
epss
|
Thu, 19 Dec 2024 14:45:00 +0000
Type | Values Removed | Values Added |
---|---|---|
First Time appeared |
Redhat
Redhat enterprise Linux |
|
CPEs | cpe:/a:redhat:enterprise_linux:9 cpe:/o:redhat:enterprise_linux:9 |
|
Vendors & Products |
Redhat
Redhat enterprise Linux |
Wed, 27 Nov 2024 02:30:00 +0000
Type | Values Removed | Values Added |
---|---|---|
Weaknesses | CWE-125 | |
Metrics |
cvssV3_1
|
cvssV3_1
|
Fri, 08 Nov 2024 16:15:00 +0000
Type | Values Removed | Values Added |
---|---|---|
References |
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Wed, 06 Nov 2024 13:45:00 +0000
Type | Values Removed | Values Added |
---|---|---|
References |
| |
Metrics |
threat_severity
|
cvssV3_1
|
Tue, 05 Nov 2024 17:30:00 +0000
Type | Values Removed | Values Added |
---|---|---|
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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|

Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2025-10-01T20:27:17.080Z
Reserved: 2024-10-21T19:36:19.947Z
Link: CVE-2024-50115

Updated: 2025-10-01T15:15:55.396Z

Status : Modified
Published: 2024-11-05T18:15:14.700
Modified: 2025-10-01T21:15:49.230
Link: CVE-2024-50115


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