CVE-2026-119135
Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Panic via StreamReader Type Mismatch
Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 panics when the host reads a component model stream as a different Rust item type than it was created with, because the host-to-host read path asserts matching TypeIds instead of returning an error. Guest code can return a host-created StreamReader<U> that the embedder reads as StreamReader<T>, where both types map to the same component model type, crashing the embedding process.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| wasmtime bytecodealliance wasmtime
cargo |
≥ 46.0.0; < 48.0.6 (affected, semver) 48.0.6 (unaffected, semver) ≥ 49.0.0; < 49.0.3 (affected, semver) 49.0.3 (unaffected, semver) Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 5.9 medium |
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 4.8 medium |
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H | CNA: VulnCheck |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-63h4-6cx9-pjfjCNA: VulnCheck · vendor-advisory
- https://www.vulncheck.com/advisories/wasmtime-46.0.0-before-48.0.6-and-49.0.0-before-49.0.3-panic-via-streamreader-type-mismatchCNA: VulnCheck · third-party-advisory
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