CVE-2026-43173 net: ethernet: xscale: Check for PTP support properly
A null pointer dereference in the Linux kernel's ixp4xx Ethernet driver allows local attackers to cause a system crash via ethtool commands.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-43173?
CVE-2026-43173 is a medium-severity vulnerability in Linux kernel, published on 6 May 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: ethernet: xscale: Check for PTP support properly
In ixp4xx_get_ts_info() ixp46x_ptp_find() is called unconditionally despite this feature only existing on ixp46x, leading to the following splat from tcpdump:
root@OpenWrt:~# tcpdump -vv -X -i eth0 (...) Unable to handle kernel NULL pointer dereference at virtual address 00000238 when read (...) Call trace: ptp_clock_index from ixp46x_ptp_find+0x1c/0x38 ixp46x_ptp_find from ixp4xx_get_ts_info+0x4c/0x64 ixp4xx_get_ts_info from __ethtool_get_ts_info+0x90/0x108 __ethtool_get_ts_info from __dev_ethtool+0xa00/0x2648 __dev_ethtool from dev_ethtool+0x160/0x234 dev_ethtool from dev_ioctl+0x2cc/0x460 dev_ioctl from sock_ioctl+0x1ec/0x524 sock_ioctl from sys_ioctl+0x51c/0xa94 sys_ioctl from ret_fast_syscall+0x0/0x44 (...) Segmentation fault
Check for ixp46x in ixp46x_ptp_find() before trying to set up PTP to avoid this.
To avoid altering the returned error code from ixp4xx_hwtstamp_set() which before this patch was -EOPNOTSUPP, we return -EOPNOTSUPP from ixp4xx_hwtstamp_set() if ixp46x_ptp_find() fails no matter the error code. The helper function ixp46x_ptp_find() helper returns -ENODEV.
Weakness: CWE-476
Which versions are affected by CVE-2026-43173?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-43173?
Apply the vendor's patch.
Is CVE-2026-43173 being exploited?
There is no known exploitation of CVE-2026-43173 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-43173, DEBIAN-CVE-2026-43173, GHSA-f26q-jhc2-x3h8, ROOT-OS-UBUNTU-2204-CVE-2026-43173, ROOT-OS-UBUNTU-2404-CVE-2026-43173, UBUNTU-CVE-2026-43173.