CVE-2023-53438
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-18

Last updated on: 2025-12-11

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: x86/MCE: Always save CS register on AMD Zen IF Poison errors The Instruction Fetch (IF) units on current AMD Zen-based systems do not guarantee a synchronous #MC is delivered for poison consumption errors. Therefore, MCG_STATUS[EIPV|RIPV] will not be set. However, the microarchitecture does guarantee that the exception is delivered within the same context. In other words, the exact rIP is not known, but the context is known to not have changed. There is no architecturally-defined method to determine this behavior. The Code Segment (CS) register is always valid on such IF unit poison errors regardless of the value of MCG_STATUS[EIPV|RIPV]. Add a quirk to save the CS register for poison consumption from the IF unit banks. This is needed to properly determine the context of the error. Otherwise, the severity grading function will assume the context is IN_KERNEL due to the m->cs value being 0 (the initialized value). This leads to unnecessary kernel panics on data poison errors due to the kernel believing the poison consumption occurred in kernel context.
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Meta Information
Published
2025-09-18
Last Modified
2025-12-11
Generated
2026-05-07
AI Q&A
2025-09-18
EPSS Evaluated
2026-05-05
NVD
CVE-2023-53438
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
linux linux_kernel to 6.1.53 (exc)
linux linux_kernel From 6.2 (inc) to 6.4.16 (exc)
linux linux_kernel From 6.5 (inc) to 6.5.3 (exc)
Helpful Resources
Exploitability
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CWE ID Description
CWE-NVD-CWE-noinfo
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability involves the Linux kernel on AMD Zen-based systems where the Instruction Fetch (IF) units do not guarantee a synchronous Machine Check (#MC) for poison consumption errors. As a result, certain status bits (MCG_STATUS[EIPV|RIPV]) are not set, making it difficult to determine the exact instruction pointer at the time of the error. The kernel incorrectly assumes the error occurred in kernel context because the Code Segment (CS) register was not saved properly and defaults to zero. This causes unnecessary kernel panics. The fix adds a quirk to always save the CS register on these errors to correctly identify the error context and avoid false kernel panics.


How can this vulnerability impact me? :

This vulnerability can cause unnecessary kernel panics on AMD Zen-based systems when data poison errors occur. The kernel mistakenly believes the error happened in kernel context due to missing CS register information, leading to system crashes and instability. This can result in unexpected downtime and potential data loss or disruption of services running on affected systems.


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