Answer in brief
CVE-2026-126409 records a Low severity (CVSS 1.8) vulnerability in Wasmtime 47.0.0 before 48.0.8 Cross-Engine Type Confusion via StructType Supertype. The current sources do not mark it as known exploited. The current feed maps bytecodealliance/wasmtime (generic), bytecodealliance/wasmtime (generic), bytecodealliance/wasmtime (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 1.8. 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 bytecodealliance/wasmtime (generic), bytecodealliance/wasmtime (generic), bytecodealliance/wasmtime (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| bytecodealliance/wasmtimegeneric | >=47.0.0 <48.0.8 | 48.0.8 |
| bytecodealliance/wasmtimegeneric | >=49.0.0 <49.0.5 | 49.0.5 |
| bytecodealliance/wasmtimegeneric | >=50.0.0 <50.0.1 | 50.0.1 |
Published upstream
Nov 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 13, 2026
Wasmtime 47.0.0 before 48.0.8, 49.0.0 before 49.0.5, and 50.0.0 before 50.0.1 contains a cross-engine type confusion vulnerability because StructType::with_finality_and_supertype does not validate that the supplied supertype belongs to the same Engine. Embedders using multiple engines that create a GC struct type with another engine's supertype can trigger runtime panics or GC heap corruption, causing denial of service; guest WebAssembly cannot trigger it.
Quoted source text, attributed separately from HOL analysis.