CVE-2025-38579: Debian Linux

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

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.

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 5.15, before 5.15.190 (fixed in 5.15.190); from 5.16, before 6.1.148 (fixed in 6.1.148); from 6.2, before 6.6.102 (fixed in 6.6.102); from 6.7, before 6.12.42 (fixed in 6.12.42); from 6.13, before 6.15.10 (fixed in 6.15.10); from 6.16, before 6.16.1 (fixed in 6.16.1)

Published 2025-08-19. Last modified 2026-07-30.