Answer in brief
CVE-2025-39823 records a High severity (CVSS 7.8) vulnerability in KVM: x86: use array_index_nospec with indices that come from guest. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC CN 4100 (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC CN 4100 (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=4180bf1b655a791a0a6ef93a2ffffc762722c782 <72777fc31aa7ab2ce00f44bfa3929c6eabbeaf48 || >=4180bf1b655a791a0a6ef93a2ffffc762722c782 <31a0ad2f60cb4816e06218b63e695eb72ce74974 || >=4180bf1b655a791a0a6ef93a2ffffc762722c782 <d51e381beed5e2f50f85f49f6c90e023754efa12 || >=4180bf1b655a791a0a6ef93a2ffffc762722c782 <33e974c2d5a82b2f9d9ba0ad9cbaabc1c8e3985f || >=4180bf1b655a791a0a6ef93a2ffffc762722c782 <f49161646e03d107ce81a99c6ca5da682fe5fb69 || >=4180bf1b655a791a0a6ef93a2ffffc762722c782 <67a05679621b7f721bdba37a5d18665d3aceb695 || >=4180bf1b655a791a0a6ef93a2ffffc762722c782 <f57a4bd8d6cb5af05b8ac1be9098e249034639fb || >=4180bf1b655a791a0a6ef93a2ffffc762722c782 <c87bd4dd43a624109c3cc42d843138378a7f4548 | 72777fc31aa7ab2ce00f44bfa3929c6eabbeaf48, 31a0ad2f60cb4816e06218b63e695eb72ce74974, d51e381beed5e2f50f85f49f6c90e023754efa12, 33e974c2d5a82b2f9d9ba0ad9cbaabc1c8e3985f, f49161646e03d107ce81a99c6ca5da682fe5fb69, 67a05679621b7f721bdba37a5d18665d3aceb695, f57a4bd8d6cb5af05b8ac1be9098e249034639fb, c87bd4dd43a624109c3cc42d843138378a7f4548 |
| Linux/Linuxgeneric | 4.19 | Not reported |
| Siemens/SIMATIC CN 4100generic | >=0 <V5.0 | V5.0 |
Published upstream
Sep 16, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 28, 2026
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.
Quoted source text, attributed separately from HOL analysis.