ghsa-mjgv-4grg-pfrr
Vulnerability from github
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.
{
"affected": [],
"aliases": [
"CVE-2024-50115"
],
"database_specific": {
"cwe_ids": [
"CWE-125"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-11-05T18:15:14Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: nSVM: Ignore nCR3[4:0] when loading PDPTEs from memory\n\nIgnore nCR3[4:0] when loading PDPTEs from memory for nested SVM, as bits\n4:0 of CR3 are ignored when PAE paging is used, and thus VMRUN doesn\u0027t\nenforce 32-byte alignment of nCR3.\n\nIn the absolute worst case scenario, failure to ignore bits 4:0 can result\nin an out-of-bounds read, e.g. if the target page is at the end of a\nmemslot, and the VMM isn\u0027t using guard pages.\n\nPer the APM:\n\n The CR3 register points to the base address of the page-directory-pointer\n table. The page-directory-pointer table is aligned on a 32-byte boundary,\n with the low 5 address bits 4:0 assumed to be 0.\n\nAnd the SDM\u0027s much more explicit:\n\n 4:0 Ignored\n\nNote, KVM gets this right when loading PDPTRs, it\u0027s only the nSVM flow\nthat is broken.",
"id": "GHSA-mjgv-4grg-pfrr",
"modified": "2024-11-08T21:33:53Z",
"published": "2024-11-05T18:32:12Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-50115"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2c4adc9b192a0815fe58a62bc0709449416cc884"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/426682afec71ea3f889b972d038238807b9443e4"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/58cb697d80e669c56197f703e188867c8c54c494"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6876793907cbe19d42e9edc8c3315a21e06c32ae"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/76ce386feb14ec9a460784fcd495d8432acce7a5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f559b2e9c5c5308850544ab59396b7d53cfc67bd"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
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