CVE-2025-38560
BaseFortify
Publication date: 2025-08-19
Last updated on: 2025-11-03
Assigner: kernel.org
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | 6.1.153 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability is related to the Linux kernel's handling of memory validation for Secure Nested Paging (SNP) on x86 systems. Specifically, when a page's state changes to private, a cache coherency issue can occur if cache lines are not properly evicted. The mitigation involves touching the first and last byte of each 4K page during validation to ensure cache lines are evicted and maintain coherency. This is only necessary if a specific CPU bit (COHERENCY_SFW_NO) is not set, indicating the system is vulnerable.
How can this vulnerability impact me? :
If unmitigated, this vulnerability could lead to cache coherency issues during memory validation in SNP environments, potentially causing incorrect memory states or security risks related to stale or inconsistent data in the cache. This could affect the integrity and security of memory operations in virtualized or secure environments relying on SNP.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
Detection involves checking the CPUID bit Fn8000001F_EBX[31] (COHERENCY_SFW_NO). If this bit is set, the software mitigation is not needed, indicating the system is not vulnerable. You can use CPU feature detection tools or commands like 'cpuid' or 'lscpu' with appropriate flags to inspect this bit. However, specific commands to directly detect this vulnerability are not provided.
What immediate steps should I take to mitigate this vulnerability?
The mitigation is to implement cache line eviction by touching the first and last byte of each 4K page during memory validation when changing page state to private. This mitigation should be invoked only if the COHERENCY_SFW_NO bit is not set. Immediate steps include updating the Linux kernel to a version that includes this fix and ensuring the mitigation is applied during SNP memory validation.