CVE-2026-119135
Wasmtime 46.0.0 before 48.0.6 and 49.0.0 before 49.0.3 Panic via StreamReader Type Mismatch
CVSS Score
4.8
EPSS Score
0.0%
EPSS Percentile
0th
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.
| CWE | CWE-617 |
| Vendor | bytecodealliance |
| Product | wasmtime |
| Published | Oct 29, 2026 |
Stay Ahead of the Next One
Get instant alerts for bytecodealliance wasmtime
Be the first to know when new medium vulnerabilities affecting bytecodealliance wasmtime are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
bytecodealliance / wasmtime
46.0.0 < 48.0.6 49.0.0 < 49.0.3
References
Credits
🔍 tschneidereit