Description
In the Linux kernel, the following vulnerability has been resolved:
vhost: fix vhost_get_avail_idx for a non empty ring
vhost_get_avail_idx is supposed to report whether it has updated
vq->avail_idx. 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
vhost_get_avail_idx propagates through vhost_enable_notify 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
vhost_enable_notify()") which changed vhost_enable_notify() to compare
the freshly read avail index against vq->last_avail_idx instead of the
previously cached vq->avail_idx. Commit 7ad472397667 ("vhost: move
smp_rmb() into vhost_get_avail_idx()") then carried over the same
comparison when refactoring vhost_enable_notify() to call the unified
vhost_get_avail_idx().
The obvious fix is to make vhost_get_avail_idx do what the comment
says it does and report whether new entries have been added.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Linux | Linux | 5.18 | 6.1.191 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | linux | 7.1.5-1 | — |
| Debian 13 | linux | 6.12.100-1 | — |
| Debian 12 | linux | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Nvidia-BlueField 24.04 LTS | linux-bluefield | 6.8.0-1033.38 | — |
| Ubuntu 26.04 LTS | linux | 7.0.0-38.38 | USN-8887-1 |
| Ubuntu 26.04 LTS | linux-aws +1 | 7.0.0-1014.14 | USN-8887-1 |
| Ubuntu 26.04 LTS | linux-azure | 7.0.0-1017.17 | USN-8888-1 |
| Ubuntu 26.04 LTS | linux-azure-fde | 7.0.0-1016.16 | USN-8888-1 |
| Ubuntu 26.04 LTS | linux-gke | 7.0.0-1008.9 | USN-8887-1 |
| Ubuntu 26.04 LTS | linux-ibm +1 | 7.0.0-1015.15 | USN-8889-1, USN-8887-1 |
| Ubuntu 26.04 LTS | linux-nvidia | 7.0.0-1025.26 | USN-9043-1 |
| Ubuntu 26.04 LTS | linux-nvidia-bos | 7.0.0-2022.23 | USN-9003-1 |
| Ubuntu 26.04 LTS | linux-oracle | 7.0.0-1013.13 | USN-8887-1 |
| Ubuntu 26.04 LTS | linux-raspi | 7.0.0-1023.23 | USN-9021-1 |
| Ubuntu 26.04 LTS | linux-riscv +1 | 7.0.0-38.38.1 | USN-8887-1 |
| Ubuntu 24.04 LTS | linux | 6.8.0-147.147 | USN-8917-1 |
| Ubuntu 24.04 LTS | linux-aws +1 | 6.8.0-1067.70 | USN-9024-1, USN-8917-1 |
| Ubuntu 24.04 LTS | linux-aws-7.0 +1 | 7.0.0-1014.14~24.04.1 | USN-8887-3, USN-8887-2 |
| Ubuntu 24.04 LTS | linux-azure-7.0 | 7.0.0-1017.17~24.04.1 | USN-8888-2 |
| Ubuntu 24.04 LTS | linux-azure-fde | 6.8.0-1069.76 | USN-8918-1 |
| Ubuntu 24.04 LTS | linux-azure-fde-7.0 | 7.0.0-1016.16~24.04.1 | USN-8888-2 |
| Ubuntu 24.04 LTS | linux-gcp +1 | 6.8.0-1071.79 | USN-8918-1, USN-8917-1 |
| Ubuntu 24.04 LTS | linux-gke | 6.8.0-1066.74 | USN-8917-1 |
| Ubuntu 24.04 LTS | linux-gkeop | 6.8.0-1052.56 | USN-8917-1 |
| Ubuntu 24.04 LTS | linux-hwe-7.0 | 7.0.0-38.38~24.04.4 | USN-8887-3 |
| Ubuntu 24.04 LTS | linux-ibm | 6.8.0-1067.68 | USN-8917-1 |
| Ubuntu 24.04 LTS | linux-lowlatency | 6.8.0-147.147.1 | USN-8917-1 |
| Ubuntu 24.04 LTS | linux-nvidia-7.0 | 7.0.0-1024.25~24.04.1 | USN-9003-1 |
| Ubuntu 24.04 LTS | linux-nvidia-lowlatency | 6.8.0-1067.70.1 | USN-9040-1 |
| Ubuntu 24.04 LTS | linux-nvidia-tegra | 6.8.0-1036.39 | USN-8886-1 |
| Ubuntu 24.04 LTS | linux-oracle | 6.8.0-1064.67 | USN-8917-1 |
| Ubuntu 24.04 LTS | linux-oracle-7.0 | 7.0.0-1013.13~24.04.1 | USN-8887-3 |
| Ubuntu 24.04 LTS | linux-raspi | 6.8.0-1068.72 | USN-9025-1 |
| Ubuntu 24.04 LTS | linux-riscv +29 | No fix yet | — |
| Ubuntu 24.04 LTS | linux-riscv-7.0 | 7.0.0-38.38.1~24.04.1 | — |
| Ubuntu 24.04 LTS | linux-vmware | 6.8.0-1008.8 | — |
| Ubuntu 22.04 LTS | linux-aws-6.8 | 6.8.0-1069.74~22.04.1 | USN-9024-1 |
| Ubuntu 22.04 LTS | linux-azure-6.8 | 6.8.0-1073.82~22.04.1 | USN-9026-1 |
| Ubuntu 22.04 LTS | linux-azure-fde-6.8 | 6.8.0-1071.78~22.04.1 | USN-9026-1 |
| Ubuntu 22.04 LTS | linux-gcp-6.8 | 6.8.0-1073.81~22.04.1 | USN-9024-1 |
| Ubuntu 22.04 LTS | linux-hwe-6.8 | 6.8.0-149.149~22.04.1 | USN-9066-1 |
| Ubuntu 22.04 LTS | linux-ibm-6.8 | 6.8.0-1069.70~22.04.1 | USN-9024-1 |
| Ubuntu 22.04 LTS | linux-lowlatency-hwe-6.8 | 6.8.0-149.149.1~22.04.1 | USN-9024-1 |
| Ubuntu 22.04 LTS | linux-oracle-6.8 | 6.8.0-1067.71~22.04.1 | USN-9025-1 |
| Ubuntu 22.04 LTS | linux-riscv +33 | No fix yet | — |
| Ubuntu 20.04 LTS | linux-gke +28 | No fix yet | — |
Show 5 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | linux-gcp +14 | No fix yet | — |
| Ubuntu 16.04 LTS | linux-hwe-edge | No fix yet | — |
| Ubuntu Pro Realtime 24.04 LTS | linux-raspi-realtime | 6.8.0-2056.58 | USN-9025-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime | 6.8.1-1062.63 | USN-8917-1 |
| Ubuntu Pro Realtime 24.04 LTS | linux-realtime-6.14 +1 | No fix yet | — |
| Ubuntu Pro Realtime 22.04 LTS | linux-realtime-6.8 | 6.8.1-1064.65~22.04.1 | USN-9024-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-aws-fips | 6.8.0-1067.70+fips1 | USN-8917-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-fips | 6.8.0-147.147+fips1 | USN-8917-1 |
| Ubuntu Pro FIPS-updates 24.04 LTS | linux-gcp-fips +1 | 6.8.0-1071.79+fips1 | USN-8918-1, USN-8917-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | kernel-64kb +7 | 6.4.0-150700.53.84.1 | SUSE-SU-2026:4706-1 |
| SLES 15 SP7 | kernel-default-base | 6.4.0-150700.53.84.1.150700.17.47.1 | SUSE-SU-2026:4706-1 |
| SLES 15 SP6 | kernel-64kb +6 | 6.4.0-150600.23.138.1 | SUSE-SU-2026:4660-1 |
| SLES 15 SP6 | kernel-default-base | 6.4.0-150600.23.138.1.150600.12.64.1 | SUSE-SU-2026:4660-1 |
Show 9 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | kernel-64kb +8 | 6.12.0-160000.39.1 | SUSE-SU-2026:24235-1 |
| SLES for SAP 16.0 | kernel-default-base | 6.12.0-160000.39.1.160000.2.26 | SUSE-SU-2026:24235-1 |
| SLES for SAP 15 SP6 | kernel-default-base | 6.4.0-150600.23.138.1.150600.12.64.1 | SUSE-SU-2026:4660-1 |
| SLES for SAP 15 SP6 | kernel-docs +4 | 6.4.0-150600.23.138.1 | SUSE-SU-2026:4660-1 |
| SLES 16.0 | kernel-64kb +8 | 6.12.0-160000.39.1 | SUSE-SU-2026:24235-1, SUSE-SU-2026:24197-1 |
| SLES 16.0 | kernel-default-base | 6.12.0-160000.39.1.160000.2.26 | SUSE-SU-2026:24235-1 |
| SLE Micro 6.2 | kernel-default-base | 6.12.0-160000.39.1.160000.2.26 | SUSE-SU-2026:24184-1 |
| SLE Micro 6.2 | kernel-rt +5 | 6.12.0-160000.39.1 | SUSE-SU-2026:24184-1, SUSE-SU-2026:24179-1 |
| SLE Micro 6.2 | podman | 5.4.2-160000.6.1 | SUSE-SU-2026:24182-1 |
| SLE Micro 6.1 | kernel-default-base | 6.4.0-159998.53.1.159998.21.38 | SUSE-SU-2026:24181-1 |
| SLE Micro 6.1 | kernel-rt +4 | 6.4.0-159998.53.1 | SUSE-SU-2026:24182-1, SUSE-SU-2026:24181-1 |
| SLE Micro 6.0 | kernel-default-base | 6.4.0-159998.53.1.159998.21.38 | SUSE-SU-2026:24315-1 |
| SLE Micro 6.0 | kernel-rt +4 | 6.4.0-159998.53.1 | SUSE-SU-2026:24316-1, SUSE-SU-2026:24315-1 |
| SLE Live Patching 15 SP7 | kernel-default | 6.4.0-150700.53.84.1 | SUSE-SU-2026:4706-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7-RT_Update_21 | 1-150700.1.3.1 | SUSE-SU-2026:4640-1 |
| SLE Live Patching 15 SP7 | kernel-livepatch-SLE15-SP7_Update_22 | 1-150700.15.3.1 | SUSE-SU-2026:4706-1 |
| SLE Live Patching 15 SP6 | kernel-default | 6.4.0-150600.23.138.1 | SUSE-SU-2026:4660-1 |
| SLE Live Patching 15 SP6 | kernel-livepatch-SLE15-SP6_Update_32 | 1-150600.13.3.1 | SUSE-SU-2026:4660-1 |
| SUSE Real Time Module 15 SP7 | kernel-rt +2 | 6.4.0-150700.7.78.1 | SUSE-SU-2026:4640-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | kernel-default-base | 6.12.0-160000.39.1.160000.2.25 | openSUSE-SU-2026:22091-1 |
| openSUSE Leap 16.0 | kernel-rt +11 | 6.12.0-160000.39.1 | openSUSE-SU-2026:22091-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | kernel-livepatch-6.18.41-94.142 +2 | 1:1.0-0.amzn2023 | ALAS2023-2026-3389, ALAS2023-2026-2071, ALAS2023-2026-2057 |
| Amazon Linux 2023 | perf +12 | 1:6.1.190-237.431.amzn2023 | ALAS2023-2026-3389 |
| Amazon Linux 2023 | perf6.12 +11 | 1:6.12.100-125.179.amzn2023 | ALAS2023-2026-2057 |
| Amazon Linux 2023 | perf6.18 +12 | 1:6.18.41-94.142.amzn2023 | ALAS2023-2026-2071 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | kernel | 6.6.161.1-1 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 9 | kernel-uek +34 | 6.12.0-206.104.3.3.el10uek | ELSA-2026-500248 |
Advisories 34
- USN-9066-1 linux-hwe-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9021-1 linux-raspi vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9024-1 linux-aws-6.8, linux-gcp-6.8, linux-ibm-6.8, linux-lowlatency-hwe-6.8, linux-nvidia, linux-realtime-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9026-1 linux-azure-6.8, linux-azure-fde-6.8 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- WID-SEC-2026-2852 Linux Kernel: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 12, 2026
- USN-9040-1 linux-nvidia-lowlatency vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9043-1 linux-nvidia vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8917-1 linux, linux-aws, linux-aws-fips, linux-fips, linux-gcp, linux-gcp-fips, linux-gke, linux-gkeop, linux-ibm, linux-lowlatency, linux-oracle, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9025-1 linux-oracle-6.8, linux-raspi, linux-raspi-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8887-1 linux, linux-aws, linux-gcp, linux-gke, linux-ibm, linux-oracle, linux-realtime vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8887-3 linux-gcp-7.0, linux-hwe-7.0, linux-oracle-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-9003-1 linux-nvidia-7.0, linux-nvidia-bos vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8888-2 linux-azure-7.0, linux-azure-fde-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8918-1 linux-azure, linux-azure-fde, linux-azure-fips vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8888-1 linux-azure, linux-azure-fde vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8887-2 linux-aws-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8889-1 linux-oem-7.0 vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- USN-8886-1 linux-nvidia-tegra vulnerabilities Ubuntu Security Notices (USN) · Nov 12, 2026
- ALAS2023-2026-3389 Important: kernel security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Nov 11, 2026
- SUSE-SU-2026:24315-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 27, 2026
- SUSE-SU-2026:24316-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 27, 2026
- SUSE-SU-2026:24235-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 21, 2026
- SUSE-SU-2026:24197-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 21, 2026
- SUSE-SU-2026:24184-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 20, 2026
- SUSE-SU-2026:24179-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 20, 2026
- SUSE-SU-2026:24181-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 20, 2026
- SUSE-SU-2026:24182-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 20, 2026
- openSUSE-SU-2026:22091-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 19, 2026
- SUSE-SU-2026:4706-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 17, 2026
- SUSE-SU-2026:4660-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 14, 2026
- SUSE-SU-2026:4640-1 Security update for the Linux Kernel SUSE / openSUSE Security Updates · Oct 14, 2026
- ALAS2023-2026-2071 Important: kernel6.18 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 15, 2026
- ALAS2023-2026-2057 Important: kernel6.12 security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Sep 9, 2026
- ELSA-2026-500248 Important: Unbreakable Enterprise kernel security update (Oracle Linux 9) Oracle Linux Security Advisories (ELSA) · Sep 4, 2026
References
- https://git.kernel.org/stable/c/7536f8f72bd24f1ae316c24231faaa3667eba837
- https://git.kernel.org/stable/c/0fe5ca2d56f0122988016e415a074c95925504b7
- https://git.kernel.org/stable/c/e115471008111f894c6528d9ab2ce7d0ce306f35
- https://git.kernel.org/stable/c/7f229d27bf27c7e589eca690d8612763a7a4801f
- https://git.kernel.org/stable/c/a9326b652bc7acd748d7a1143573845c7924d847
- https://git.kernel.org/stable/c/09861858a68342f851f71c669ac0f69865c32151