CVE-2025-38579 Information

Aug 20, 2025 cve

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.

Reference

https://git.kernel.org/stable/c/01b6f5955e0008af6bc3a181310d2744bb349800 https://git.kernel.org/stable/c/154467f4ad033473e5c903a03e7b9bca7df9a0fa https://git.kernel.org/stable/c/44a79437309e0ee2276ac17aaedc71253af253a8 https://git.kernel.org/stable/c/cc1615d5aba4f396cf412579928539a2b124c8a0 https://git.kernel.org/stable/c/dabfa3952c8e6bfe6414dbf32e8b6c5f349dc898 https://git.kernel.org/stable/c/e68b751ec2b15d866967812c57cfdfc1eba6a269

CNNVD-202508-2144 (Published: 2025-08-19)

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