Copyright © 2012 Red Hat, Inc. All rights reserved. Low 2026-07-24T00:00:00 kernel: net: ethtool: phy: avoid NULL deref when PHY driver is unbound 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-476

In the Linux kernel, the following vulnerability has been resolved: net: ethtool: phy: avoid NULL deref when PHY driver is unbound phydev->drv can become NULL while the phy_device is still attached to its net_device, namely after the PHY driver is unbound via sysfs: echo <mdio_id> > /sys/bus/mdio_bus/drivers/<phy_drv>/unbind phy_remove() clears phydev->drv but doesn't call phy_detach(), so the phy_device stays in the link topology xarray and ethnl_req_get_phydev() still hands it back. ETHTOOL_MSG_PHY_GET then oopses on: rep_data->drvname = kstrdup(phydev->drv->name, GFP_KERNEL); drvname is already treated as optional by phy_reply_size(), phy_fill_reply() and phy_cleanup_data(), so just skip the allocation when there is no driver bound.

A flaw was found in the Linux kernel's ethtool PHY (Physical Layer) driver. A local attacker can trigger a null pointer dereference by unbinding a PHY driver via sysfs while the device is still attached. This can lead to a kernel crash, resulting in a denial of service.

Red Hat Enterprise Linux 10 Fix deferred kernel Red Hat Enterprise Linux 10 Fix deferred libkrun Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt Red Hat Enterprise Linux for NVIDIA 26 Out of support scope kernel Red Hat OpenShift Container Platform 4 Fix deferred rhcos https://www.cve.org/CVERecord?id=CVE-2026-64228 https://nvd.nist.gov/vuln/detail/CVE-2026-64228 https://lore.kernel.org/linux-cve-announce/2026072418-CVE-2026-64228-064a@gregkh/T