Answer in brief
CVE-2026-63940 records a Unknown severity vulnerability in KVM: SEV: Ignore Port I/O requests of length '0'. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. 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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=291bd20d5d88814a73d43b55b9428feab2f28094 <3b6035bc6bff20e89752ce4358bc4c9a9d5883f2 || >=291bd20d5d88814a73d43b55b9428feab2f28094 <2254972d4d69e279ba4e87bf0968eb08ad0d3c92 || >=291bd20d5d88814a73d43b55b9428feab2f28094 <c30cde934c7813b4e3069765dac64ce3d31e34f2 || >=291bd20d5d88814a73d43b55b9428feab2f28094 <3988bd2723de407ae90fa7a6f6029b4e60238c58 | 3b6035bc6bff20e89752ce4358bc4c9a9d5883f2, 2254972d4d69e279ba4e87bf0968eb08ad0d3c92, c30cde934c7813b4e3069765dac64ce3d31e34f2, 3988bd2723de407ae90fa7a6f6029b4e60238c58 |
| Linux/Linuxgeneric | 5.11 | Not reported |
Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Ignore Port I/O requests of length '0' Explicitly ignore Port I/O requests of length '0' (or count '0'), so that setting up the software scratch area (and other code) doesn't have to worry about underflowing the length, and to allow for WARNing on trying to configure the scratch area with len==0.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-63940 records a Unknown severity vulnerability in KVM: SEV: Ignore Port I/O requests of length '0'. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. 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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=291bd20d5d88814a73d43b55b9428feab2f28094 <3b6035bc6bff20e89752ce4358bc4c9a9d5883f2 || >=291bd20d5d88814a73d43b55b9428feab2f28094 <2254972d4d69e279ba4e87bf0968eb08ad0d3c92 || >=291bd20d5d88814a73d43b55b9428feab2f28094 <c30cde934c7813b4e3069765dac64ce3d31e34f2 || >=291bd20d5d88814a73d43b55b9428feab2f28094 <3988bd2723de407ae90fa7a6f6029b4e60238c58 | 3b6035bc6bff20e89752ce4358bc4c9a9d5883f2, 2254972d4d69e279ba4e87bf0968eb08ad0d3c92, c30cde934c7813b4e3069765dac64ce3d31e34f2, 3988bd2723de407ae90fa7a6f6029b4e60238c58 |
| Linux/Linuxgeneric | 5.11 | Not reported |
Published upstream
Jul 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Ignore Port I/O requests of length '0' Explicitly ignore Port I/O requests of length '0' (or count '0'), so that setting up the software scratch area (and other code) doesn't have to worry about underflowing the length, and to allow for WARNing on trying to configure the scratch area with len==0.
Quoted source text, attributed separately from HOL analysis.