UBUNTU-CVE-2026-68152: Use After Free
In the Linux kernel, the following vulnerability has been resolved: amt: fix use-after-free in AMT delayed works When an AMT device is removed, pending delayed works can still access the freed amtdev structure, which may result in kernel crashes or memory corruption. amtdevstop() cancels reqwq and discoverywq with canceldelayedworksync(), but these works can be scheduled again from eventwq after the cancellation. This allows delayed works to access the freed amtdev structure after the netdev has been released. The following is a simple race scenario: CPU0 CPU1 amtdevstop() canceldelayedworksync() amteventwork() moddelayedwork(reqwq) free netdev reqwq accesses freed amtdev Use disabledelayedworksync() in amtdevstop() to prevent reqwq and discoverywq from being queued again and wait for running work items to complete. The delayed works are disabled after initialization in amtnewlink() and enabled only when the device is successfully opened. This keeps the delayed work lifecycle synchronized with the lifetime of the AMT device.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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ubuntu/linux-aws-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
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ubuntu/linux-azure-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17~24.04.1 - Upgrade
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ubuntu/linux-azure-fde-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1016.16~24.04.1 - Upgrade
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ubuntu/linux-gcp-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1014.14~24.04.1 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38~24.04.4 - Upgrade
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ubuntu/linux-nvidia-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1024.25~24.04.1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1035.38 - Upgrade
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ubuntu/linux-oracle-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1013.13~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-38.38 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 7.0.0-1016.16 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1014.14 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 7.0.0-1008.9 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
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ubuntu/linux-nvidia-bosto a version that resolves this vulnerability.Fixed in 7.0.0-2022.23 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1015.15 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1013.13 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-38.38.1 - Compensating control
In amt_dev_stop(), use disable_delayed_work_sync() for req_wq and discovery_wq to prevent event_wq from re-queuing them and to wait for running work items to complete before freeing the netdev.
Event History
Frequently Asked Questions
What level of access does an attacker need?
The vulnerability is locally exploitable and requires low privileges. It does not require user interaction, but exploitation has high attack complexity and depends on additional attack requirements being present.
Which Ubuntu kernel packages are identified as affected?
The listed packages are ubuntu/linux-riscv, ubuntu/linux-realtime, ubuntu/linux-azure, ubuntu/linux-gcp, ubuntu/linux-azure-fde, ubuntu/linux-gke, ubuntu/linux-hwe-edge, and ubuntu/linux-gkeop.
When is the vulnerable condition reachable?
It is associated with removal of an AMT device while delayed work can be queued again by event work after cancellation. The affected delayed work is enabled only after the AMT device has been successfully opened.
What impact can successful exploitation have?
A successful race can cause delayed work to access a freed AMT device structure after the network device is released. This may result in kernel crashes or memory corruption, with high confidentiality, integrity, and availability impact in the supplied severity vector.