CVE-2026-53231 net: phy: don't try to setup PHY-driven SFP cages when using genphy

What is CVE-2026-53231?

CVE-2026-53231 is a medium-severity vulnerability in Linux kernel, published on 25 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

net: phy: don't try to setup PHY-driven SFP cages when using genphy

We don't have support for PHY-driver SFP cages with the genphy code.

On top of that, it was found by sashiko that running sfp_bus_add_upstream() for genphy deadlocks, as for genphy the PHY probing runs under RTNL, which isn't the case for non-genphy drivers.

This problem was reproduced, and does lead to a deadlock on RTNL.

Before the blamed commit, the phy_sfp_probe() call was made by individual PHY drivers, so there was no way to get to the SFP probing path when using genphy.

Let's therefore only run phy_sfp_probe when not using genphy.

Weakness: CWE-667

Which versions are affected by CVE-2026-53231?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-53231?

Apply the vendor's patch.

Is CVE-2026-53231 being exploited?

There is no known exploitation of CVE-2026-53231 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2026-53231, GHSA-cmgx-qw5m-5j29, UBUNTU-CVE-2026-53231.