CVE-2026-99062: vsock/virtio: account only unread bytes in read_skb()

Q: What conditions are needed to trigger the accounting error?

The issue occurs on a connected CID_LOCAL VSOCK stream using an SK_SKB verdict, after a packet is only partially received. The faulty path is virtio_transport_read_skb(), where the packet is dequeued.

Q: How can I tell whether a system is exhibiting this issue?

Observed symptoms include SIOCINQ returning a negative value after a partial read, an empty recv returning ELOOP, and poll reporting an empty socket as readable. After verdict detach, queued bytes may be hidden until an additional byte arrives.

Q: What does the fix change?

The fix subtracts only the unread portion of the skb, excluding the VSOCK offset, from rx_bytes. It continues to use the full packet length for buf_used and peer credit, keeping receive accounting balanced and making queued data immediately visible.

Published Oct 23, 2026

Updated

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

vsock/virtio: account only unread bytes in readskb()

After a partial stream receive, rxbytes tracks the unread suffix while bufused and peer credit still cover the whole packet. virtiotransportreadskb() dequeues that packet but passes pktlen for both counters, underflowing rxbytes.

On a connected CIDLOCAL stream with an SKSKB verdict, a 40-byte read from a 100-byte packet made SIOCINQ report -40, an empty recv return ELOOP, and poll report the empty socket readable. After verdict detach, receiving 40 bytes wrapped the counter to zero and hid those queued bytes until one more byte arrived. The fixed run kept the counter balanced and exposed all queued data immediately.

This was found during an LLM-assisted manual source audit of VSOCK receive accounting while re-evaluating virtiotransportreadskb() after CVE-2024-50169.

Subtract only skb->len minus the VSOCK offset from rxbytes. Retain the full packet length for bufused and peer credit.

Affected Software

173 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<6.8.0-1069.74~22.04.1

6.8.0-1069.74~22.04.1

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1073.82~22.04.1

6.8.0-1073.82~22.04.1

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1071.78~22.04.1

6.8.0-1071.78~22.04.1

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1073.81~22.04.1

6.8.0-1073.81~22.04.1

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-ibm-6.8<6.8.0-1069.70~22.04.1

6.8.0-1069.70~22.04.1

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<6.8.0-149.149.1~22.04.1

6.8.0-149.149.1~22.04.1

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<6.8.0-1067.71~22.04.1

6.8.0-1067.71~22.04.1

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-149.149~22.04.2

6.8.0-149.149~22.04.2

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-realtime-6.8<6.8.1-1064.65~22.04.1

6.8.1-1064.65~22.04.1

ubuntu/linux<6.8.0-149.149

6.8.0-149.149

ubuntu/linux-aws<6.8.0-1069.74

6.8.0-1069.74

ubuntu/linux-aws-6.14*

ubuntu/linux-aws-6.17*

ubuntu/linux-aws-7.0<7.0.0-1017.18~24.04.1

7.0.0-1017.18~24.04.1

ubuntu/linux-azure<6.8.0-1073.82

6.8.0-1073.82

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-6.14*

ubuntu/linux-azure-6.17*

ubuntu/linux-azure-7.0*

ubuntu/linux-azure-fde<6.8.0-1071.78

6.8.0-1071.78

ubuntu/linux-azure-fde-6.14*

ubuntu/linux-azure-fde-6.17*

ubuntu/linux-azure-fde-7.0<7.0.0-1019.19~24.04.1

7.0.0-1019.19~24.04.1

ubuntu/linux-azure-nvidia*

ubuntu/linux-azure-nvidia-6.14*

ubuntu/linux-gcp<6.8.0-1073.81

6.8.0-1073.81

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14*

ubuntu/linux-gcp-7.0<7.0.0-1017.19~24.04.1

7.0.0-1017.19~24.04.1

ubuntu/linux-gke<6.8.0-1068.77

6.8.0-1068.77

ubuntu/linux-gkeop<6.8.0-1053.57

6.8.0-1053.57

ubuntu/linux-hwe-6.11*

ubuntu/linux-hwe-6.14*

ubuntu/linux-hwe-6.17*

ubuntu/linux-hwe-7.0*

ubuntu/linux-ibm<6.8.0-1069.70

6.8.0-1069.70

ubuntu/linux-lowlatency<6.8.0-149.149.1

6.8.0-149.149.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1067.70

6.8.0-1067.70

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-6.17*

ubuntu/linux-nvidia-7.0*

ubuntu/linux-nvidia-lowlatency<6.8.0-1067.70.1

6.8.0-1067.70.1

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<6.8.0-1067.71

6.8.0-1067.71

ubuntu/linux-oracle-6.14*

ubuntu/linux-oracle-6.17*

ubuntu/linux-oracle-7.0<7.0.0-1016.18~24.04.1

7.0.0-1016.18~24.04.1

ubuntu/linux-raspi<6.8.0-1068.72

6.8.0-1068.72

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<7.0.0-43.43.1~24.04.2

7.0.0-43.43.1~24.04.2

ubuntu/linux-vmware<6.8.0-1010.10

6.8.0-1010.10

ubuntu/linux-xilinx*

ubuntu/linux-bluefield<6.8.0-1036.41

6.8.0-1036.41

ubuntu/linux-raspi-realtime<6.8.0-2056.58

6.8.0-2056.58

ubuntu/linux-realtime<6.8.1-1064.65

6.8.1-1064.65

ubuntu/linux-realtime-6.14*

ubuntu/linux-realtime-6.17*

ubuntu/linux-aws-fips<6.8.0-1069.74+fips1

6.8.0-1069.74+fips1

ubuntu/linux-azure-fips<6.8.0-1073.82+fips1

6.8.0-1073.82+fips1

ubuntu/linux-fips*

ubuntu/linux-gcp-fips<6.8.0-1073.81+fips1

6.8.0-1073.81+fips1

ubuntu/linux<7.3.0-10.10

7.3.0-10.10

ubuntu/linux-aws<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-azure<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-azure-fde<7.3.0-1004.5

7.3.0-1004.5

ubuntu/linux-gcp<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-oracle<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-raspi<7.3.0-1004.4

7.3.0-1004.4

ubuntu/linux-realtime<7.3.0-10.10.1

7.3.0-10.10.1

ubuntu/linux-riscv<7.3.0-10.10.1

7.3.0-10.10.1

ubuntu/linux<7.0.0-43.43

7.0.0-43.43

ubuntu/linux-aws<7.0.0-1017.18

7.0.0-1017.18

ubuntu/linux-azure<7.0.0-1020.21

7.0.0-1020.21

ubuntu/linux-azure-fde<7.0.0-1019.19

7.0.0-1019.19

ubuntu/linux-gcp<7.0.0-1017.19

7.0.0-1017.19

ubuntu/linux-gke<7.0.0-1010.11

7.0.0-1010.11

ubuntu/linux-ibm<7.0.0-1018.18

7.0.0-1018.18

ubuntu/linux-nvidia*

ubuntu/linux-nvidia-bos*

ubuntu/linux-oem-7.0<7.0.0-1018.18

7.0.0-1018.18

ubuntu/linux-oracle<7.0.0-1016.18

7.0.0-1016.18

ubuntu/linux-raspi<7.0.0-1023.23

7.0.0-1023.23

ubuntu/linux-realtime<7.0.0-43.43.1

7.0.0-43.43.1

ubuntu/linux-riscv*

ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.74~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.82~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1071.78~22.04.1
Upgrade
Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.81~22.04.1
Upgrade
Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.70~22.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-149.149.1~22.04.1
Upgrade
Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.71~22.04.1
Upgrade
Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-149.149~22.04.2
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1064.65~22.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-149.149
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.74
Upgrade
Upgrade ubuntu/linux-aws-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.18~24.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.82
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 6.8.0-1071.78
Upgrade
Upgrade ubuntu/linux-azure-fde-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1019.19~24.04.1
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.81
Upgrade
Upgrade ubuntu/linux-gcp-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.19~24.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1068.77
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1053.57
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.70
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-149.149.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.70
Upgrade
Upgrade ubuntu/linux-nvidia-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.70.1
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 6.8.0-1067.71
Upgrade
Upgrade ubuntu/linux-oracle-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1016.18~24.04.1
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 6.8.0-1068.72
Upgrade
Upgrade ubuntu/linux-riscv-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-43.43.1~24.04.2
Upgrade
Upgrade ubuntu/linux-vmware to a version that resolves this vulnerability.
Fixed in 6.8.0-1010.10
Upgrade
Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 6.8.0-1036.41
Upgrade
Upgrade ubuntu/linux-raspi-realtime to a version that resolves this vulnerability.
Fixed in 6.8.0-2056.58
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 6.8.1-1064.65
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1069.74+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.82+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1073.81+fips1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 7.3.0-10.10
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.5
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 7.3.0-1004.4
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 7.3.0-10.10.1
Upgrade
Upgrade ubuntu/linux-riscv to a version that resolves this vulnerability.
Fixed in 7.3.0-10.10.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 7.0.0-43.43
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.18
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 7.0.0-1020.21
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 7.0.0-1019.19
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 7.0.0-1017.19
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 7.0.0-1010.11
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 7.0.0-1018.18
Upgrade
Upgrade ubuntu/linux-oem-7.0 to a version that resolves this vulnerability.
Fixed in 7.0.0-1018.18
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 7.0.0-1016.18
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 7.0.0-1023.23
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 7.0.0-43.43.1

Event History

Oct 23, 2026

CVE Published

via MITRE·12:23 PM

Data Sourced

via MITRE·12:23 PM

Description

Data Sourced

via OSV·01:17 PM

DescriptionSeverityAffected Software

Data Sourced

via NVD·01:17 PM

Description

Frequently Asked Questions

What conditions are needed to trigger the accounting error?

The issue occurs on a connected CID_LOCAL VSOCK stream using an SK_SKB verdict, after a packet is only partially received. The faulty path is virtio_transport_read_skb(), where the packet is dequeued.

How can I tell whether a system is exhibiting this issue?

Observed symptoms include SIOCINQ returning a negative value after a partial read, an empty recv returning ELOOP, and poll reporting an empty socket as readable. After verdict detach, queued bytes may be hidden until an additional byte arrives.

What does the fix change?

The fix subtracts only the unread portion of the skb, excluding the VSOCK offset, from rx_bytes. It continues to use the full packet length for buf_used and peer credit, keeping receive accounting balanced and making queued data immediately visible.

CVE-2026-99062: vsock/virtio: account only unread bytes in read_skb()

Affected Software

Remediation

Event History

Frequently Asked Questions

What conditions are needed to trigger the accounting error?

How can I tell whether a system is exhibiting this issue?

What does the fix change?

Company

Resources

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