CVE-2025-39823

KVM: x86: use array_index_nospec with indices that come from guest

HIGH

7.8

CVSS Score

Published: September 16, 2025 at 01:00 PM UTC

Updated: October 19, 2026 at 09:10 PM UTC

3 products affected across 3 vendorsLinux KernelDebian LinuxSIMATIC CN 4100

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Severity

HIGH7.8

Exploit prediction

EPSS 0.2%

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Debian Linux · Debiandrupal

95%

11.0

Linux Kernel · Linux

95%

4.19 ≤ v < 5.4.2985.11 ≤ v < 5.15.1915.16 ≤ v < 6.1.1505.5 ≤ v < 5.10.2426.13 ≤ v < 6.16.56.2 ≤ v < 6.6.1046.7 ≤ v < 6.12.454.194180bf1b655a791a0a6ef93a2ffffc762722c7826.17 6.17 rc1 6.17 rc2 6.17 rc3

Vendor states this is fixed in 31a0ad2f60cb4816e06218b63e695eb72ce74974 (fixed)

Vendor states this is fixed in 33e974c2d5a82b2f9d9ba0ad9cbaabc1c8e3985f (fixed)

Vendor states this is fixed in 67a05679621b7f721bdba37a5d18665d3aceb695 (fixed)

Vendor states this is fixed in 72777fc31aa7ab2ce00f44bfa3929c6eabbeaf48 (fixed)

Vendor states this is fixed in c87bd4dd43a624109c3cc42d843138378a7f4548 (fixed)

Vendor states this is fixed in d51e381beed5e2f50f85f49f6c90e023754efa12 (fixed)

Vendor states this is fixed in f49161646e03d107ce81a99c6ca5da682fe5fb69 (fixed)

Vendor states this is fixed in f57a4bd8d6cb5af05b8ac1be9098e249034639fb (fixed)

Vendor states this is fixed in 4.19 (unaffected)

Vendor states this is fixed in 5.10.242 (unaffected)

Vendor states this is fixed in 5.15.191 (unaffected)

Vendor states this is fixed in 5.4.298 (unaffected)