CVE-2025-38579: debian linux — Fix

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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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-908 CWE-908

Affected Products

Vendor	Product	Versions
linux	linux_kernel	5.15 — 5.15.190
linux	linux_kernel	5.16 — 6.1.148
linux	linux_kernel	6.2 — 6.6.102
linux	linux_kernel	6.7 — 6.12.42
linux	linux_kernel	6.13 — 6.15.10
linux	linux_kernel	6.16 — 6.16.1
debian	debian_linux	All

References

Advisories & Patches

https://git.kernel.org/stable/c/01b6f5955e0008af6bc3a181310d2744bb349800 https://git.kernel.org/stable/c/08e8ab00a6d20d5544c932ee85a297d833895141 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

Other References

https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html

Frequently Asked Questions

What is CVE-2025-38579? +

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. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2025-38579? +

CVE-2025-38579 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-38579? +

CVE-2025-38579 affects products from debian, linux, specifically: debian_linux, linux_kernel. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-38579? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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