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 2 October 2026.

Which products and versions are affected?

Bytecode Alliance Wasmtime-Wasi-Http 46.0.0 through 48.0.3, 49.0.0 and 49.0.1; wasmtime-wasi-http (crates.io) SEMVER:introduced=46.0.0,fixed=48.0.4,introduced=49.0.0,fixed=49.0.2.

Is there a fix for This vulnerability?

Yes. wasmtime-wasi-http (crates.io): upgrade to 49.0.2 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.

Check whether you run Bytecode Alliance Wasmtime-Wasi-Http or wasmtime-wasi-http (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.

Wasmtime wasi:http implementation panic with zero timeout

Severity: medium · CVSS 4 · Published 2026-10-02

Wasmtime is a WebAssembly runtime that allows secure execution of untrusted code. A flaw in its HTTP request handling component causes the service to crash (panic) when a WebAssembly application supplies a zero timeout value. An attacker with limited privileges who can control WebAssembly input can trigger a denial-of-service condition affecting availability.

Technologies: wasmtime-wasi-http (crates.io). Vendors: Bytecode Alliance, crates.io.

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 2 October 2026.
Which products and versions are affected?: Bytecode Alliance Wasmtime-Wasi-Http 46.0.0 through 48.0.3, 49.0.0 and 49.0.1; wasmtime-wasi-http (crates.io) SEMVER:introduced=46.0.0,fixed=48.0.4,introduced=49.0.0,fixed=49.0.2.
Is there a fix for This vulnerability?: Yes. wasmtime-wasi-http (crates.io): upgrade to 49.0.2 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.
Am I affected?: Check whether you run Bytecode Alliance Wasmtime-Wasi-Http or wasmtime-wasi-http (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-wasi-http (crates.io): upgrade to 49.0.2 or later
```
cargo update -p wasmtime-wasi-http
```

Technical details

The wasmtime-wasi-http library panics when a zero timeout is supplied to HTTP request operations, caused by improper input validation. The vulnerability requires network access, low privileges, and user interaction (passive). An attacker can crash the Wasmtime runtime, causing service unavailability. Fixes are available in versions 48.0.4+ and 49.0.2+.

Affected products

Bytecode Alliance wasmtime-wasi-http 46.0.0 through 48.0.3, 49.0.0 and 49.0.1

Identifiers

GHSA-w4qr-p94g-mjhv
RUSTSEC-2026-0320

Timeline

2026-10-02: disclosed

References

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