CVE-2025-38579

f2fs: fix KMSAN uninit-value in extent_info usage

State: Published
Severity: 7.8 High
Published: Aug 19, 2025
Updated: Aug 5, 2026
Reserved: Apr 16, 2025

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.

Scores

CVSS	Score	Vector	Source
3.1	7.8 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H	Linux

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	94afd6d6e5253179c9b891d02081cc8355a11768 to before 08e8ab00a6d20d5544c932ee85a297d833895141Affected 94afd6d6e5253179c9b891d02081cc8355a11768 to before e68b751ec2b15d866967812c57cfdfc1eba6a269Affected 94afd6d6e5253179c9b891d02081cc8355a11768 to before dabfa3952c8e6bfe6414dbf32e8b6c5f349dc898Affected 94afd6d6e5253179c9b891d02081cc8355a11768 to before 44a79437309e0ee2276ac17aaedc71253af253a8Affected 94afd6d6e5253179c9b891d02081cc8355a11768 to before cc1615d5aba4f396cf412579928539a2b124c8a0Affected 94afd6d6e5253179c9b891d02081cc8355a11768 to before 01b6f5955e0008af6bc3a181310d2744bb349800Affected 94afd6d6e5253179c9b891d02081cc8355a11768 to before 154467f4ad033473e5c903a03e7b9bca7df9a0faAffected
LinuxLinux	5.15Affected before 5.15Not affected 5.15.190 through 5.15.Not affected 6.1.148 through 6.1.Not affected 6.6.102 through 6.6.Not affected 6.12.42 through 6.12.Not affected 6.15.10 through 6.15.Not affected 6.16.1 through 6.16.Not affected 6.17 and laterNot affected

Product

Versions

LinuxLinux

94afd6d6e5253179c9b891d02081cc8355a11768 to before 08e8ab00a6d20d5544c932ee85a297d833895141Affected
94afd6d6e5253179c9b891d02081cc8355a11768 to before e68b751ec2b15d866967812c57cfdfc1eba6a269Affected
94afd6d6e5253179c9b891d02081cc8355a11768 to before dabfa3952c8e6bfe6414dbf32e8b6c5f349dc898Affected
94afd6d6e5253179c9b891d02081cc8355a11768 to before 44a79437309e0ee2276ac17aaedc71253af253a8Affected
94afd6d6e5253179c9b891d02081cc8355a11768 to before cc1615d5aba4f396cf412579928539a2b124c8a0Affected
94afd6d6e5253179c9b891d02081cc8355a11768 to before 01b6f5955e0008af6bc3a181310d2744bb349800Affected
94afd6d6e5253179c9b891d02081cc8355a11768 to before 154467f4ad033473e5c903a03e7b9bca7df9a0faAffected

LinuxLinux

5.15Affected
before 5.15Not affected
5.15.190 through 5.15.*Not affected
6.1.148 through 6.1.*Not affected
6.6.102 through 6.6.*Not affected
6.12.42 through 6.12.*Not affected
6.15.10 through 6.15.*Not affected
6.16.1 through 6.16.*Not affected
6.17 and laterNot affected

References

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