Quick answers
- Is This vulnerability exploited in the wild?
- No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
- How severe is This vulnerability?
- Medium severity, with a CVSS score of 4, published 14 October 2026.
- Which products and versions are affected?
- Bytecode Alliance Wasmtime 46.0.0 to <48.0.6, 49.0.0 to <49.0.3; wasmtime (crates.io) SEMVER:introduced=46.0.0,fixed=48.0.6,introduced=49.0.0,fixed=49.0.3.
- Is there a fix for This vulnerability?
- Yes. wasmtime (crates.io): upgrade to 49.0.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is This vulnerability attacked?
- It is attacked over the network, in a software library.
- Am I affected?
- Check whether you run Bytecode Alliance Wasmtime or wasmtime (crates.io) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- wasmtime (crates.io): upgrade to 49.0.3 or later
cargo update -p wasmtime
Technical details
The vulnerability occurs in Wasmtime's component model when handling stream or future types: if an attacker views these values as an incorrect type, a panic is triggered in the vulnerable system. This requires network access, low privileges, and passive user interaction. The issue causes high availability impact to the Wasmtime instance itself (denial of service) but no confidentiality or integrity compromise. Patches are available in versions 48.0.6, 49.0.3, and later.
Affected products
- Bytecode Alliance Wasmtime 46.0.0 to <48.0.6, 49.0.0 to <49.0.3
Identifiers
- GHSA-63h4-6cx9-pjfj
- RUSTSEC-2026-0355
Timeline
- 2026-10-14: disclosed