CVSS 4.0
1.8 lowCVSS:4.0/AV:N/AC:H/AT:P/PR:H/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NCVE-2026-126409 Wasmtime 47.0.0 before 48.0.8 Cross-Engine Type Confusion via StructType Supertype
Low (1.8) in bytecodealliance wasmtime. EPSS 0.3% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
CVSS 3.1
2.0 lowCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:N/I:N/A:L- EPSS
- 0.3% estimated probability of exploitation activity in the next 30 days; 20th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CWE
- CWE-843 Access of Resource Using Incompatible Type (Type Confusion)
- Published
- Modified
- Assigned by
- VulnCheck (CNA)
- NVD analysis
- Deferred: the NVD does not plan to analyze it
- Record from
- the NVD, synced
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| bytecodealliance wasmtime | from 47.0.0 before 48.0.8 |
| bytecodealliance wasmtime | from 49.0.0 before 49.0.5 |
| bytecodealliance wasmtime | from 50.0.0 before 50.0.1 |
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Ubuntu | 24.04:LTS, 26.04:LTS, 26.10 | rust-wasmtime | no fix listed | UBUNTU-CVE-2026-126409 |
From the distributions' data via OSV.dev: Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Ubuntu.
History
- The NVD deferred its analysis
Changes since this site first stored the record. The same for every record: /api/public/changes.