Bug 2389488 (CVE-2025-38579) - CVE-2025-38579 kernel: f2fs: fix KMSAN uninit-value in extent_info usage
Summary: CVE-2025-38579 kernel: f2fs: fix KMSAN uninit-value in extent_info usage
Keywords:
Status: NEW
Alias: CVE-2025-38579
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2025-08-19 18:03 UTC by OSIDB Bzimport
Modified: 2025-08-20 17:30 UTC (History)
0 users

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2025-08-19 18:03:39 UTC
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.


Note You need to log in before you can comment on or make changes to this bug.