🛡️ UBUNTU-CVE-2025-40300
⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

In the Linux kernel, the following vulnerability has been resolved: x86/vmscape: Add conditional IBPB mitigation VMSCAPE is a vulnerability that exploits insufficient branch predictor isolation between a guest and a userspace hypervisor (like QEMU). Existing mitigations already protect kernel/KVM from a malicious guest. Userspace can additionally be protected by flushing the branch predictors after a VMexit. Since it is the userspace that consumes the poisoned branch predictors, conditionally issue an IBPB after a VMexit and before returning to userspace. Workloads that frequently switch between hypervisor and userspace will incur the most overhead from the new IBPB. This new IBPB is not integrated with the existing IBPB sites. For instance, a task can use the existing speculation control prctl() to get an IBPB at context switch time. With this implementation, the IBPB is doubled up: one at context switch and another before running userspace. The intent is to integrate and optimize these cases post-embargo. [ dhansen: elaborate on suboptimal IBPB solution ]

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2025-09-11
Updated 2026-06-15
Modified 2026-06-08
Fix URL N/A

Affected Packages

Software From version Fixed in
linux 6.8.0-87.88
linux-allwinner-5.19
linux-aws 6.8.0-1042.44
linux-aws-5.0
linux-aws-5.11
linux-aws-5.13
linux-aws-5.15 5.15.0-1096.103~20.04.1
linux-aws-5.19
linux-aws-5.3
linux-aws-5.4 5.4.0-1152.162~18.04.1
linux-aws-5.8
linux-aws-6.14 6.14.0-1016.16~24.04.1
linux-aws-6.2
linux-aws-6.5
linux-aws-6.8 6.8.0-1042.44~22.04.1
linux-aws-fips 6.8.0-1042.44+fips1
linux-aws-hwe 4.15.0-1186.199~16.04.1
linux-azure 6.8.0-1044.50
linux-azure-4.15 4.15.0-1194.209
linux-azure-5.11
linux-azure-5.13
linux-azure-5.15 5.15.0-1102.111~20.04.1
linux-azure-5.19
linux-azure-5.3
linux-azure-5.4 5.4.0-1156.163~18.04.1
linux-azure-5.8
linux-azure-6.11
linux-azure-6.14 6.14.0-1017.17~24.04.1
linux-azure-6.2
linux-azure-6.5
linux-azure-6.8 6.8.0-1044.50~22.04.1
linux-azure-edge
linux-azure-fde
linux-azure-fde-5.15
linux-azure-fde-5.19
linux-azure-fde-6.14
linux-azure-fde-6.17
linux-azure-fde-6.2
linux-azure-fde-6.8
linux-azure-fips 6.8.0-1044.50+fips1
linux-azure-nvidia 6.8.0-1029.32
linux-azure-nvidia-6.14
linux-bluefield
linux-fips 6.8.0-87.88+fips1
linux-gcp 6.8.0-1043.46
linux-gcp-4.15 4.15.0-1179.196
linux-gcp-5.11
linux-gcp-5.13
linux-gcp-5.15 5.15.0-1096.105~20.04.1
linux-gcp-5.19
linux-gcp-5.3
linux-gcp-5.4 5.4.0-1155.164~18.04.1
linux-gcp-5.8
linux-gcp-6.11
linux-gcp-6.14 6.14.0-1019.20~24.04.1
linux-gcp-6.2
linux-gcp-6.5
linux-gcp-6.8 6.8.0-1043.46~22.04.1
linux-gcp-fips 6.8.0-1043.46+fips1
linux-gke 6.8.0-1039.44
linux-gke-4.15
linux-gke-5.15
linux-gke-5.4
linux-gkeop 6.8.0-1026.29
linux-gkeop-5.15
linux-gkeop-5.4
linux-hwe
linux-hwe-5.11
linux-hwe-5.13
linux-hwe-5.15 5.15.0-161.171~20.04.1
linux-hwe-5.19
linux-hwe-5.4 5.4.0-223.243~18.04.1
linux-hwe-5.8
linux-hwe-6.11
linux-hwe-6.2
linux-hwe-6.5
linux-hwe-6.8 6.8.0-87.88~22.04.1
linux-hwe-edge
linux-ibm 6.8.0-1040.40
linux-ibm-5.15 5.15.0-1090.93~20.04.1
linux-ibm-5.4 5.4.0-1098.103~18.04.1
linux-ibm-6.8 6.8.0-1040.40~22.04.1
linux-intel
linux-intel-5.13
linux-intel-iot-realtime 5.15.0-1088.90
linux-intel-iotg 5.15.0-1091.97
linux-intel-iotg-5.15 5.15.0-1091.97~20.04.1
linux-iot 5.4.0-1056.59
linux-kvm 5.15.0-1089.94
linux-lowlatency 6.8.0-87.88.1
linux-lowlatency-hwe-5.15 5.15.0-161.171~20.04.1
linux-lowlatency-hwe-5.19
linux-lowlatency-hwe-6.11
linux-lowlatency-hwe-6.2
linux-lowlatency-hwe-6.5
linux-lowlatency-hwe-6.8 6.8.0-87.88.1~22.04.1
linux-lts-xenial 4.4.0-274.308~14.04.1
linux-nvidia 6.8.0-1042.45
linux-nvidia-6.11
linux-nvidia-6.2
linux-nvidia-6.5
linux-nvidia-6.8 6.8.0-1042.45~22.04.1
linux-nvidia-lowlatency 6.8.0-1042.45.1
linux-nvidia-tegra 6.8.0-1012.12
linux-nvidia-tegra-5.15 5.15.0-1048.48~20.04.1
linux-nvidia-tegra-igx 5.15.0-1037.37
linux-oem
linux-oem-5.10
linux-oem-5.13
linux-oem-5.14
linux-oem-5.17
linux-oem-5.6
linux-oem-6.0
linux-oem-6.1
linux-oem-6.11
linux-oem-6.14 6.14.0-1015.15
linux-oem-6.5
linux-oem-6.8
linux-oracle 6.8.0-1039.40
linux-oracle-5.0
linux-oracle-5.11
linux-oracle-5.13
linux-oracle-5.15 5.15.0-1093.99~20.04.1
linux-oracle-5.3
linux-oracle-5.4 5.4.0-1150.160~18.04.1
linux-oracle-5.8
linux-oracle-6.14 6.14.0-1016.16~24.04.1
linux-oracle-6.5
linux-oracle-6.8 6.8.0-1039.40~22.04.1
linux-raspi 6.8.0-1042.46
linux-raspi-5.4 5.4.0-1135.148~18.04.1
linux-raspi-realtime 6.8.0-2033.34
linux-raspi2
linux-realtime 6.8.1-1037.38
linux-realtime-6.14 6.14.0-1015.15~24.04.1
linux-realtime-6.8 6.8.1-1037.38~22.04.1
linux-riscv
linux-riscv-5.11
linux-riscv-5.15 5.15.0-1091.95~20.04.1
linux-riscv-5.19
linux-riscv-5.8
linux-riscv-6.14 6.14.0-35.35.1~24.04.1
linux-riscv-6.5
linux-riscv-6.8 6.8.0-87.88~22.04.1
linux-starfive-5.19
linux-starfive-6.2
linux-starfive-6.5
linux-xilinx 6.8.0-1019.20
linux-xilinx-zynqmp 5.15.0-1060.64

References

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