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Vulnerability · Published Sep 16, 2025 · Assigned by Linux

CVE-2025-39823KVM: x86: use array_index_nospec with indices that come from guest

High 7.8

In plain English

A high-severity security flaw in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 8% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)7.8High
Exploit odds (30 days)0.2%top 92.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: use array_index_nospec with indices that come from guest min and dest_id are guest-controlled indices. Using array_index_nospec() after the bounds checks clamps these values to mitigate speculative execution side-channels.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.153-1DEBIAN-CVE-2025-39823
Debian:13linux6.12.48-1DEBIAN-CVE-2025-39823
Debian:14linux6.16.5-1DEBIAN-CVE-2025-39823
Ubuntu:22.04:LTSlinux5.15.0-163.173UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux6.8.0-106.106USN-8095-1
Ubuntu:24.04:LTSlinux6.8.0-106.106UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-aws5.15.0-1097.104UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-aws6.8.0-1050.53UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-aws6.8.0-1050.53USN-8095-1
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1050.53~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1050.53~22.04.1USN-8095-4
Ubuntu:22.04:LTSlinux-azure5.15.0-1101.110UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-azure6.8.0-1051.57UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-azure6.8.0-1051.57USN-8125-1
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1051.57~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1102.111.1UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1058.65UBUNTU-CVE-2025-39823
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1058.65~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-gcp5.15.0-1097.106UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-gcp6.8.0-1052.55UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-gcp6.8.0-1052.55USN-8095-1
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1052.55~22.04.1USN-8095-1
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1052.55~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-gke5.15.0-1093.99UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-gke6.8.0-1048.53UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-gke6.8.0-1048.53USN-8095-1
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1080.88UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1035.38UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1035.38USN-8095-1
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-106.106~22.04.1USN-8095-1
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-ibm5.15.0-1091.94UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-ibm6.8.0-1049.49USN-8095-1
Ubuntu:24.04:LTSlinux-ibm6.8.0-1049.49UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1049.49~22.04.1USN-8095-1
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1049.49~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-intelno fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1092.98UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-kvm5.15.0-1089.94UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-163.173UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-106.106.1UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-106.106.1USN-8095-1
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-106.106.1~22.04.1USN-8095-1
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-106.106.1~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1092.93UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1049.52USN-8100-1
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1049.52UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1049.52~22.04.1USN-8100-1
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1049.52~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1049.52.1UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1049.52.1USN-8100-1
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1049.49UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1020.20UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1038.38UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-oracle5.15.0-1094.100UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-oracle6.8.0-1047.48UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-oracle6.8.0-1047.48USN-8095-1
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1047.48~22.04.1USN-8095-1
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1047.48~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-raspi5.15.0-1091.94UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-raspi6.8.0-1050.54UBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-raspi6.8.0-1050.54USN-8095-5
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-106.106~22.04.1UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2025-39823
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1029.30USN-8261-1
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1028.29UBUNTU-CVE-2025-39823
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1061.65UBUNTU-CVE-2025-39823

Affected products (as reported)

VendorProductVersions
Linux Linux 4180bf1b655a791a0a6ef93a2ffffc762722c782 – before 72777fc31aa7ab2ce00f44bfa3929c6eabbeaf484180bf1b655a791a0a6ef93a2ffffc762722c782 – before 31a0ad2f60cb4816e06218b63e695eb72ce749744180bf1b655a791a0a6ef93a2ffffc762722c782 – before d51e381beed5e2f50f85f49f6c90e023754efa124180bf1b655a791a0a6ef93a2ffffc762722c782 – before 33e974c2d5a82b2f9d9ba0ad9cbaabc1c8e3985f4180bf1b655a791a0a6ef93a2ffffc762722c782 – before f49161646e03d107ce81a99c6ca5da682fe5fb694180bf1b655a791a0a6ef93a2ffffc762722c782 – before 67a05679621b7f721bdba37a5d18665d3aceb6954180bf1b655a791a0a6ef93a2ffffc762722c782 – before f57a4bd8d6cb5af05b8ac1be9098e249034639fb4180bf1b655a791a0a6ef93a2ffffc762722c782 – before c87bd4dd43a624109c3cc42d843138378a7f4548
Linux Linux 4.19

References