CVE-2025-38086: In the Linux kernel, the following vulnerability has been resolved: net: ch9200: fix uninitialised access during mii_nway_restart In mii_nway_restar...

Description

In the Linux kernel, the following vulnerability has been resolved: net: ch9200: fix uninitialised access during mii_nway_restart In mii_nway_restart() the code attempts to call mii->mdio_read which is ch9200_mdio_read(). ch9200_mdio_read() utilises a local buffer called "buff", which is initialised with control_read(). However "buff" is conditionally initialised inside control_read(): if (err == size) { memcpy(data, buf, size); } If the condition of "err == size" is not met, then "buff" remains uninitialised. Once this happens the uninitialised "buff" is accessed and returned during ch9200_mdio_read(): return (buff[0] | buff[1] << 8); The problem stems from the fact that ch9200_mdio_read() ignores the return value of control_read(), leading to uinit-access of "buff". To fix this we should check the return value of control_read() and return early on error.

Metrics

CVSS 3.1

5.5/10

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

EPSS Probability

0.15%

4.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-908

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	>= 4.3.1, < 5.4.295
Linux	Linux Kernel	>= 5.5, < 5.10.239
Linux	Linux Kernel	>= 5.11, < 5.15.186
Linux	Linux Kernel	>= 5.16, < 6.1.142
Linux	Linux Kernel	>= 6.2, < 6.6.95
Linux	Linux Kernel	>= 6.7, < 6.12.35
Linux	Linux Kernel	>= 6.13, < 6.15.4
Linux	Linux Kernel	4.3
Debian	Debian Linux	11.0

References

Timeline

Published: Jun 28, 2025
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2025-38086?

In the Linux kernel, the following vulnerability has been resolved: net: ch9200: fix uninitialised access during mii_nway_restart In mii_nway_restart() the code attempts to call mii->mdio_read which is ch9200_mdio_read(). ch9200_mdio_read() utilises a local buffer called "buff", which is initialised with control_read(). However "buff" is conditionally initialised inside control_read(): if (err == size) { memcpy(data, buf, size); } If the condition of "err == size" is not met, then "buff" remains uninitialised. Once this happens the uninitialised "buff" is accessed and returned during ch9200_mdio_read(): return (buff[0] | buff[1] << 8); The problem stems from the fact that ch9200_mdio_read() ignores the return value of control_read(), leading to uinit-access of "buff". To fix this we should check the return value of control_read() and return early on error.

How severe is CVE-2025-38086?

CVE-2025-38086 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.15% probability of exploitation in the next 30 days.

How do I fix CVE-2025-38086?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.