CVE-2025-38110: net/mdiobus: Fix potential out-of-bounds clause 45 read/write access

Vulnerability summary

CVE-2025-38110 is a high (CVSS 7.8) Out-of-bounds Read vulnerability in linux. EPSS estimates a 0.20% chance of exploitation in the next 30 days, higher than 9.5% of scored vulnerabilities.

Timeline

1. 03-07-2025
   PublishedVulnerability first disclosed.
2. 15-10-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: net/mdiobus: Fix potential out-of-bounds clause 45 read/write access When using publicly available tools like 'mdio-tools' to read/write data from/to network interface and its PHY via C45 (clause 45) mdiobus, there is no verification of parameters passed to the ioctl and it accepts any mdio address. Currently there is support for 32 addresses in kernel via PHY_MAX_ADDR define, but it is possible to pass higher value than that via ioctl. While read/write operation should generally fail in this case, mdiobus provides stats array, where wrong address may allow out-of-bounds read/write. Fix that by adding address verification before C45 read/write operation. While this excludes this access from any statistics, it improves security of read/write operation.

• CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.