CVE-2025-38579
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-08-19

Last updated on: 2025-11-03

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: f2fs: fix KMSAN uninit-value in extent_info usage KMSAN reported a use of uninitialized value in `__is_extent_mergeable()` and `__is_back_mergeable()` via the read extent tree path. The root cause is that `get_read_extent_info()` only initializes three fields (`fofs`, `blk`, `len`) of `struct extent_info`, leaving the remaining fields uninitialized. This leads to undefined behavior when those fields are accessed later, especially during extent merging. Fix it by zero-initializing the `extent_info` struct before population.
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Meta Information
Published
2025-08-19
Last Modified
2025-11-03
Generated
2026-05-06
AI Q&A
2025-08-19
EPSS Evaluated
2026-05-05
NVD
CVE-2025-38579
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel 6.1.153-1
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability in the Linux kernel's f2fs filesystem involves the use of uninitialized values in the extent_info structure. Specifically, the function get_read_extent_info initializes only some fields of extent_info, leaving others uninitialized. When these uninitialized fields are accessed later during extent merging operations, it causes undefined behavior. The issue was detected by KMSAN (Kernel Memory Sanitizer) and fixed by zero-initializing the entire extent_info structure before use.


How can this vulnerability impact me? :

The vulnerability can lead to undefined behavior in the Linux kernel when handling filesystem extent merging in f2fs. This could potentially cause system instability, crashes, or data corruption due to the use of uninitialized memory values.


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