UBUNTU-CVE-2026-43173: Null Pointer Dereference
In the Linux kernel, the following vulnerability has been resolved: net: ethernet: xscale: Check for PTP support properly In ixp4xxgettsinfo() ixp46xptpfind() 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: ptpclockindex from ixp46xptpfind+0x1c/0x38 ixp46xptpfind from ixp4xxgettsinfo+0x4c/0x64 ixp4xxgettsinfo from ethtoolgettsinfo+0x90/0x108 ethtoolgettsinfo from devethtool+0xa00/0x2648 devethtool from devethtool+0x160/0x234 devethtool from devioctl+0x2cc/0x460 devioctl from sockioctl+0x1ec/0x524 sockioctl from sysioctl+0x51c/0xa94 sysioctl from retfastsyscall+0x0/0x44 (...) Segmentation fault Check for ixp46x in ixp46xptpfind() before trying to set up PTP to avoid this. To avoid altering the returned error code from ixp4xxhwtstampset() which before this patch was -EOPNOTSUPP, we return -EOPNOTSUPP from ixp4xxhwtstampset() if ixp46xptpfind() fails no matter the error code. The helper function ixp46xptpfind() helper returns -ENODEV.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
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ubuntu/linux-aws-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1060.63~22.04.1 - Upgrade
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ubuntu/linux-azure-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1063.71~22.04.1 - Upgrade
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ubuntu/linux-azure-fde-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1062.69~22.04.1 - Upgrade
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ubuntu/linux-gcp-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1063.69~22.04.1 - Upgrade
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ubuntu/linux-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-136.136~22.04.1 - Upgrade
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ubuntu/linux-ibm-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1060.61~22.04.1 - Upgrade
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ubuntu/linux-lowlatency-hwe-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-134.134.1~22.04.1 - Upgrade
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ubuntu/linux-nvidia-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1058.61~22.04.1 - Upgrade
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ubuntu/linux-oracle-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-1057.58~22.04.1 - Upgrade
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ubuntu/linux-riscv-6.8to a version that resolves this vulnerability.Fixed in 6.8.0-134.134~22.04.1 - Upgrade
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ubuntu/linux-realtime-6.8to a version that resolves this vulnerability.Fixed in 6.8.1-1055.56~22.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 6.8.0-134.134 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 6.8.0-1060.63 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 6.8.0-1063.71 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 6.8.0-1062.69 - Upgrade
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ubuntu/linux-azure-nvidiato a version that resolves this vulnerability.Fixed in 6.8.0-1039.42 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 6.8.0-1063.69 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 6.8.0-1058.64 - Upgrade
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ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 6.8.0-1045.48 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 6.8.0-1060.61 - Upgrade
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ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-134.134.1 - Upgrade
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ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 6.8.0-1058.61 - Upgrade
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ubuntu/linux-nvidia-lowlatencyto a version that resolves this vulnerability.Fixed in 6.8.0-1058.61.1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1029.30 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 6.8.0-1057.58 - Upgrade
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ubuntu/linux-raspito a version that resolves this vulnerability.Fixed in 6.8.0-1060.64 - Upgrade
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ubuntu/linux-xilinxto a version that resolves this vulnerability.Fixed in 6.8.0-1032.33 - Upgrade
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ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 6.8.0-1026.30 - Upgrade
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ubuntu/linux-raspi-realtimeto a version that resolves this vulnerability.Fixed in 6.8.0-2049.50 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 6.8.1-1055.56 - Upgrade
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ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1060.63+fips1 - Upgrade
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ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1062.69+fips1 - Upgrade
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ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-134.134+fips1 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 6.8.0-1063.69+fips1
Event History
Frequently Asked Questions
Which systems are realistically exposed to this issue?
Systems using the ixp4xx Ethernet driver are exposed when the hardware does not support the ixp46x-specific PTP feature. The affected Ubuntu kernel packages listed include linux, linux-realtime, linux-azure, linux-gcp, linux-azure-fde, linux-riscv, linux-gke, and linux-gkeop.
What is required to trigger the failure?
A local user able to invoke the relevant network-device timestamp information path can trigger it. The report demonstrates a crash while running tcpdump against eth0; no user interaction is required.
What can be done before a fixed kernel is available?
Avoid querying hardware timestamp or PTP timestamp information on interfaces using the ixp4xx driver, including tools or workflows that cause the ethtool timestamp-information path to be called. Restrict local access where practical, since the attack vector is local and requires low privileges.
How can I recognize an attempted or successful trigger?
Affected systems can produce a kernel NULL pointer dereference, potentially followed by a segmentation fault in the invoking program. The kernel call trace includes ixp46x_ptp_find, ixp4xx_get_ts_info, __ethtool_get_ts_info, and the network ioctl path.