UBUNTU-CVE-2026-93097: Medium severity ubuntu/linux-hwe-edge vulnerability

Q: What systems are realistically exposed to this issue?

Systems using the listed Ubuntu Linux kernel packages and performing CXL poison-list scans are exposed. The issue depends on interaction with a CXL device that returns an empty poison payload while continuously setting CXL_POISON_FLAG_MORE.

Q: What does an attacker or faulty device need to do to trigger the problem?

The device must return count == 0 together with CXL_POISON_FLAG_MORE on every scan iteration. This prevents the record counter from advancing, causing the sysfs-triggered scan loop to run indefinitely while holding poison.mutex.

Q: What is the operational impact if the issue is triggered?

The poison scan thread hangs and holds poison.mutex. Subsequent poison operations for the affected device are blocked.

Q: What can be done if an updated kernel cannot be deployed immediately?

Avoid triggering poison-list scans against CXL devices that may be malfunctioning or untrusted. This reduces the opportunity for the affected sysfs-triggered scan path to become wedged.

Q: How can an administrator recognize that a device may already be affected?

A sysfs-triggered poison scan may hang, and later poison operations on the same device will be blocked. The condition is associated with a device repeatedly reporting an empty payload with the MORE flag set.

Published Sep 17, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved: cxl/mbox: Break poison list loop on an empty payload A device that returns count == 0 with CXLPOISONFLAGMORE set on every iteration never advances nrrecords, so the maxerrors guard never trips and the do/while loops forever while holding poison.mutex. That hangs the sysfs-triggered scan thread and blocks all subsequent poison operations on the device. The existing "Protect against an uncleared FLAGMORE" guard was intended to bound a misbehaving device but does not cover the count == 0 case. Stop the loop on an empty payload so a malfunctioning or malicious device cannot wedge the poison scan.

Affected Software

161 affected componentsFixes available

ubuntu/linux-hwe-edge*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-azure*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-oem*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.8*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.8*

ubuntu/linux-gke*

ubuntu/linux-gke-5.15*

ubuntu/linux-gkeop*

ubuntu/linux-gkeop-5.15*

ubuntu/linux-hwe-5.11*

ubuntu/linux-hwe-5.13*

ubuntu/linux-hwe-5.8*

ubuntu/linux-intel-5.13*

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.8*

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8*

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8*

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8*

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8*

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-ibm-6.8*

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8*

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8*

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8*

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-realtime-6.8*

ubuntu/linux*

ubuntu/linux-aws*

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

ubuntu/linux-aws-7.0*

ubuntu/linux-azure*

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17*

ubuntu/linux-azure-7.0*

ubuntu/linux-azure-fde*

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-fde-6.17*

ubuntu/linux-azure-fde-7.0*

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp*

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-7.0*

ubuntu/linux-gke*

ubuntu/linux-gkeop*

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17*

ubuntu/linux-hwe-7.0<7.0.0-42.42~24.04.1

7.0.0-42.42~24.04.1

ubuntu/linux-ibm*

ubuntu/linux-lowlatency*

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17*

ubuntu/linux-nvidia-7.0*

ubuntu/linux-nvidia-lowlatency*

ubuntu/linux-nvidia-tegra*

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17*

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle*

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-oracle-7.0*

ubuntu/linux-raspi*

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14*

ubuntu/linux-riscv-6.17*

ubuntu/linux-riscv-7.0<7.0.0-42.42.1~24.04.1

7.0.0-42.42.1~24.04.1

ubuntu/linux-xilinx*

ubuntu/linux-bluefield*

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux-aws-fips*

ubuntu/linux-azure-fips*

ubuntu/linux-fips*

ubuntu/linux-gcp-fips*

ubuntu/linux<7.0.0-42.42

7.0.0-42.42

ubuntu/linux-aws<7.0.0-1016.17

7.0.0-1016.17

ubuntu/linux-azure*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp<7.0.0-1016.18

7.0.0-1016.18

ubuntu/linux-gke*

ubuntu/linux-ibm<7.0.0-1017.17

7.0.0-1017.17

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-bos*

ubuntu/linux-oem-7.0<7.0.0-1017.17

7.0.0-1017.17

ubuntu/linux-oracle<7.0.0-1015.16

7.0.0-1015.16

ubuntu/linux-raspi*

ubuntu/linux-realtime*

ubuntu/linux-riscv<7.0.0-42.42.1

7.0.0-42.42.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Compensating control
In the CXL poison list scan, terminate the loop when the device returns an empty payload (count == 0), even if CXL_POISON_FLAG_MORE is set, so the scan cannot loop indefinitely while holding poison.mutex.

Event History

Sep 17, 2026

CVE Published

via OSV·05:18 PM

Data Sourced

via OSV·05:18 PM

DescriptionSeverityAffected Software

Frequently Asked Questions

What systems are realistically exposed to this issue?

Systems using the listed Ubuntu Linux kernel packages and performing CXL poison-list scans are exposed. The issue depends on interaction with a CXL device that returns an empty poison payload while continuously setting CXL_POISON_FLAG_MORE.

What does an attacker or faulty device need to do to trigger the problem?

The device must return count == 0 together with CXL_POISON_FLAG_MORE on every scan iteration. This prevents the record counter from advancing, causing the sysfs-triggered scan loop to run indefinitely while holding poison.mutex.

What is the operational impact if the issue is triggered?

The poison scan thread hangs and holds poison.mutex. Subsequent poison operations for the affected device are blocked.

What can be done if an updated kernel cannot be deployed immediately?

Avoid triggering poison-list scans against CXL devices that may be malfunctioning or untrusted. This reduces the opportunity for the affected sysfs-triggered scan path to become wedged.

How can an administrator recognize that a device may already be affected?

A sysfs-triggered poison scan may hang, and later poison operations on the same device will be blocked. The condition is associated with a device repeatedly reporting an empty payload with the MORE flag set.

UBUNTU-CVE-2026-93097: Medium severity ubuntu/linux-hwe-edge vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

What systems are realistically exposed to this issue?

What does an attacker or faulty device need to do to trigger the problem?

What is the operational impact if the issue is triggered?

What can be done if an updated kernel cannot be deployed immediately?

How can an administrator recognize that a device may already be affected?

Company

Resources

Contact

Frequently Asked Questions

What systems are realistically exposed to this issue?

What does an attacker or faulty device need to do to trigger the problem?

What is the operational impact if the issue is triggered?

What can be done if an updated kernel cannot be deployed immediately?

How can an administrator recognize that a device may already be affected?