Answer in brief
CVE-2021-46977 records a High severity (CVSS 7.8) vulnerability in KVM: VMX: Disable preemption when probing user return MSRs. 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.
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). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=4be5341026246870818e28b53202b001426a5aec <31f29749ee970c251b3a7e5b914108425940d089 || >=4be5341026246870818e28b53202b001426a5aec <5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94 || >=4be5341026246870818e28b53202b001426a5aec <e3ea1895df719c4ef87862501bb10d95f4177bed || >=4be5341026246870818e28b53202b001426a5aec <5104d7ffcf24749939bea7fdb5378d186473f890 | 31f29749ee970c251b3a7e5b914108425940d089, 5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94, e3ea1895df719c4ef87862501bb10d95f4177bed, 5104d7ffcf24749939bea7fdb5378d186473f890 |
| Linux/Linuxgeneric | 5.5 | Not reported |
Published upstream
Feb 28, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 4, 2026
In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Disable preemption when probing user return MSRs Disable preemption when probing a user return MSR via RDSMR/WRMSR. If the MSR holds a different value per logical CPU, the WRMSR could corrupt the host's value if KVM is preempted between the RDMSR and WRMSR, and then rescheduled on a different CPU. Opportunistically land the helper in common x86, SVM will use the helper in a future commit.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2021-46977 records a High severity (CVSS 7.8) vulnerability in KVM: VMX: Disable preemption when probing user return MSRs. 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.
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). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=4be5341026246870818e28b53202b001426a5aec <31f29749ee970c251b3a7e5b914108425940d089 || >=4be5341026246870818e28b53202b001426a5aec <5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94 || >=4be5341026246870818e28b53202b001426a5aec <e3ea1895df719c4ef87862501bb10d95f4177bed || >=4be5341026246870818e28b53202b001426a5aec <5104d7ffcf24749939bea7fdb5378d186473f890 | 31f29749ee970c251b3a7e5b914108425940d089, 5adcdeb57007ccf8ab7ac20bf787ffb6fafb1a94, e3ea1895df719c4ef87862501bb10d95f4177bed, 5104d7ffcf24749939bea7fdb5378d186473f890 |
| Linux/Linuxgeneric | 5.5 | Not reported |
Published upstream
Feb 28, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 4, 2026
In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Disable preemption when probing user return MSRs Disable preemption when probing a user return MSR via RDSMR/WRMSR. If the MSR holds a different value per logical CPU, the WRMSR could corrupt the host's value if KVM is preempted between the RDMSR and WRMSR, and then rescheduled on a different CPU. Opportunistically land the helper in common x86, SVM will use the helper in a future commit.
Quoted source text, attributed separately from HOL analysis.