NULL pointer dereference in Linux kernel - CVE-2026-64120

Vulnerability identifier: #VU138519

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-64120

CWE-ID: CWE-476

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to a NULL pointer dereference in net/ethtool/phy.c when processing ethtool phy reply data after memory allocation failure. A local user can trigger memory allocation failures that leave string pointers NULL to cause a denial of service.

The issue can lead to a kernel panic when phy_reply_size() calls strlen() on a NULL name pointer.

Linux kernel
Ubuntu
linux-ibm (Ubuntu package)
linux-azure (Ubuntu package)
linux-aws (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-nvidia-bos (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux-ibm (Ubuntu package) - addressed in versions 7.0.0-1008.8, 7.0.0-1010.10
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1010.10
linux-aws (Ubuntu package) - addressed in versions 7.0.0-1009.9, 7.0.0-1015.15
linux-nvidia (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1016.16~24.04.1
linux-nvidia-bos (Ubuntu package) - update to 7.0.0-2016.16

• https://git.kernel.org/stable/c/3dbe20a3809347bacda890822e7ca013bd85a18c
• https://git.kernel.org/stable/c/4908f1395fb1b832ceec11584af649874a2732ea
• https://git.kernel.org/stable/c/61f53c1e58d68723bc1db10912a53f1991f08719

• NULL pointer dereference in Linux kernel ethtool
• Ubuntu update for linux-ibm
• Ubuntu update for linux-azure
• Ubuntu update for linux-aws
• Ubuntu update for linux-nvidia-bos
• Ubuntu update for linux-nvidia