CVE-2026-74356: vhost: fix vhost_get_avail_idx for a non empty ring

Q: What is the severity of CVE-2026-74356?

The severity of CVE-2026-74356 is rated at 37.

Q: What systems are affected by CVE-2026-74356?

CVE-2026-74356 affects the Linux kernel's vhost implementation.

Q: How do I fix CVE-2026-74356?

To fix CVE-2026-74356, ensure that you have applied the latest patch for your Linux kernel.

Q: What does CVE-2026-74356 exploit?

CVE-2026-74356 exploits incorrect reporting in the vhost_get_avail_idx function related to the availability index.

Q: When was CVE-2026-74356 published?

CVE-2026-74356 was published on August 15, 2026.

Published Aug 15, 2026

Updated

In the Linux kernel, the following vulnerability has been resolved:

vhost: fix vhostgetavailidx for a non empty ring

vhostgetavailidx is supposed to report whether it has updated vq->availidx. Instead, it returns whether all entries have been consumed, which is usually the same. But not always - in drivers/vhost/net.c and when mergeable buffers have been enabled, the driver checks whether the combined entries are big enough to store an incoming packet. If not, the driver re-enables notifications with available entries still in the ring. The incorrect return value from vhostgetavailidx propagates through vhostenablenotify and causes the host to livelock if the guest is not making progress, as vhost will immediately disable notifications and retry using the available entries.

This goes back to commit d3bb267bbdcb ("vhost: cache avail index in vhostenablenotify()") which changed vhostenablenotify() to compare the freshly read avail index against vq->lastavailidx instead of the previously cached vq->availidx. Commit 7ad472397667 ("vhost: move smprmb() into vhostgetavailidx()") then carried over the same comparison when refactoring vhostenablenotify() to call the unified vhostgetavailidx().

The obvious fix is to make vhostgetavailidx do what the comment says it does and report whether new entries have been added.

Affected Software

171 affected componentsFixes available

Linux Linux kernel

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<6.8.0-147.147

6.8.0-147.147

ubuntu/linux-aws<6.8.0-1067.70

6.8.0-1067.70

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

ubuntu/linux-aws-7.0<7.0.0-1014.14~24.04.1

7.0.0-1014.14~24.04.1

ubuntu/linux-azure<6.8.0-1071.79

6.8.0-1071.79

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17*

ubuntu/linux-azure-7.0<7.0.0-1017.17~24.04.1

7.0.0-1017.17~24.04.1

ubuntu/linux-azure-fde<6.8.0-1069.76

6.8.0-1069.76

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-fde-6.17*

ubuntu/linux-azure-fde-7.0<7.0.0-1016.16~24.04.1

7.0.0-1016.16~24.04.1

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1071.79

6.8.0-1071.79

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-7.0<7.0.0-1014.14~24.04.1

7.0.0-1014.14~24.04.1

ubuntu/linux-gke<6.8.0-1066.74

6.8.0-1066.74

ubuntu/linux-gkeop<6.8.0-1052.56

6.8.0-1052.56

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17*

ubuntu/linux-hwe-7.0<7.0.0-38.38~24.04.4

7.0.0-38.38~24.04.4

ubuntu/linux-ibm<6.8.0-1067.68

6.8.0-1067.68

ubuntu/linux-lowlatency<6.8.0-147.147.1

6.8.0-147.147.1

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<6.8.0-1036.39

6.8.0-1036.39

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14*

ubuntu/linux-oem-6.17*

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1064.67

6.8.0-1064.67

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-oracle-7.0<7.0.0-1013.13~24.04.1

7.0.0-1013.13~24.04.1

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<7.0.0-38.38.1~24.04.1

7.0.0-38.38.1~24.04.1

ubuntu/linux-xilinx*

ubuntu/linux-bluefield<6.8.0-1033.38

6.8.0-1033.38

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime<6.8.1-1062.63

6.8.1-1062.63

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux-aws-fips<6.8.0-1067.70+fips1

6.8.0-1067.70+fips1

ubuntu/linux-azure-fips<6.8.0-1071.79+fips1

6.8.0-1071.79+fips1

ubuntu/linux-fips<6.8.0-147.147+fips1

6.8.0-147.147+fips1

ubuntu/linux-gcp-fips<6.8.0-1071.79+fips1

6.8.0-1071.79+fips1

ubuntu/linux<7.0.0-38.38

7.0.0-38.38

ubuntu/linux-aws<7.0.0-1014.14

7.0.0-1014.14

ubuntu/linux-azure<7.0.0-1017.17

7.0.0-1017.17

ubuntu/linux-azure-fde<7.0.0-1016.16

7.0.0-1016.16

ubuntu/linux-gcp<7.0.0-1014.14

7.0.0-1014.14

ubuntu/linux-gke<7.0.0-1008.9

7.0.0-1008.9

ubuntu/linux-ibm<7.0.0-1015.15

7.0.0-1015.15

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-bos*

ubuntu/linux-oem-7.0<7.0.0-1015.15

7.0.0-1015.15

ubuntu/linux-oracle<7.0.0-1013.13

7.0.0-1013.13

ubuntu/linux-raspi*

ubuntu/linux-realtime<7.0.0-38.38.1

7.0.0-38.38.1

ubuntu/linux-riscv<7.0.0-38.38.1

7.0.0-38.38.1

debian/linux*

debian/linux<6.12.100-1

6.12.100-1

debian/linux<7.1.5-1

7.1.5-1

linux/kernel>=5.18.0<6.1.191

6.1.191

linux/kernel>=6.2.0<6.6.160

6.6.160

linux/kernel>=6.7.0<6.12.97

6.12.97

linux/kernel>=6.13.0<6.18.40

6.18.40

linux/kernel>=6.19.0<7.1.5

7.1.5

debian/linux<=6.1.176-1, <=6.1.190-1

6.12.107-16.12.115-27.2.12-17.2.15-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-147.147
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.70
Upgrade
Upgrade ubuntu/linux-aws-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1014.14~24.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 6.8.0-1071.79
Upgrade
Upgrade ubuntu/linux-azure-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.17~24.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.76
Upgrade
Upgrade ubuntu/linux-azure-fde-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1016.16~24.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1071.79
Upgrade
Upgrade ubuntu/linux-gcp-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1014.14~24.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1066.74
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1052.56
Upgrade
Upgrade ubuntu/linux-hwe-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-38.38~24.04.4
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.68
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-147.147.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 6.8.0-1036.39
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 6.8.0-1064.67
Upgrade
Upgrade ubuntu/linux-oracle-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1013.13~24.04.1
Upgrade
Upgrade ubuntu/linux-riscv-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-38.38.1~24.04.1
Upgrade
Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 6.8.0-1033.38
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 6.8.1-1062.63
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.70+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1071.79+fips1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-147.147+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1071.79+fips1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 7.0.0-38.38
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 7.0.0-1014.14
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.17
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 7.0.0-1016.16
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 7.0.0-1014.14
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 7.0.0-1008.9
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 7.0.0-1015.15
Upgrade
Upgrade ubuntu/linux-oem-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1015.15
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 7.0.0-1013.13
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 7.0.0-38.38.1
Upgrade
Upgrade ubuntu/linux-riscv to a version that resolves this vulnerability.
Fixed in 7.0.0-38.38.1
Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 6.12.100-1
Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 7.1.5-1
Upgrade
Upgrade debian/linux to a version that resolves this vulnerability.
Fixed in 6.12.107-1Fixed in 6.12.113-1Fixed in 7.2.12-1Fixed in 7.2.14-1
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.1.191
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.6.160
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.12.97
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 6.18.40
Upgrade
Upgrade linux/Kernel to a version that resolves this vulnerability.
Fixed in 7.1.5

Event History

Aug 15, 2026

CVE Published

via MITRE·05:58 AM

Data Sourced

via MITRE·05:58 AM

DescriptionSeverity

Data Sourced

via OSV·05:58 AM

DescriptionSeverityAffected Software

Data Sourced

via NVD·06:22 AM

DescriptionSeverity

Aug 23, 2026

Data Sourced

via Microsoft·09:57 PM

DescriptionSeverityWeakness

Frequently Asked Questions

What is the severity of CVE-2026-74356?

The severity of CVE-2026-74356 is rated at 37.

What systems are affected by CVE-2026-74356?

CVE-2026-74356 affects the Linux kernel's vhost implementation.

How do I fix CVE-2026-74356?

To fix CVE-2026-74356, ensure that you have applied the latest patch for your Linux kernel.

What does CVE-2026-74356 exploit?

CVE-2026-74356 exploits incorrect reporting in the vhost_get_avail_idx function related to the availability index.

When was CVE-2026-74356 published?

CVE-2026-74356 was published on August 15, 2026.

CVE-2026-74356: vhost: fix vhost_get_avail_idx for a non empty ring

Affected Software

Remediation

Event History

Frequently Asked Questions

What is the severity of CVE-2026-74356?

What systems are affected by CVE-2026-74356?

How do I fix CVE-2026-74356?

What does CVE-2026-74356 exploit?

When was CVE-2026-74356 published?

Company

Resources

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