VYPR
Moderate severityNVD Advisory· Published Feb 24, 2026· Updated Feb 27, 2026

Wasmtime can panic when adding excessive fields to a `wasi:http/types.fields` instance

CVE-2026-27572

Description

Wasmtime is a runtime for WebAssembly. Prior to versions 24.0.6, 36.0.6, 4.0.04, 41.0.4, and 42.0.0, Wasmtime's implementation of the wasi:http/types.fields resource is susceptible to panics when too many fields are added to the set of headers. Wasmtime's implementation in the wasmtime-wasi-http crate is backed by a data structure which panics when it reaches excessive capacity and this condition was not handled gracefully in Wasmtime. Panicking in a WASI implementation is a Denial of Service vector for embedders and is treated as a security vulnerability in Wasmtime. Wasmtime 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 patch this vulnerability and return a trap to the guest instead of panicking. There are no known workarounds at this time. Embedders are encouraged to update to a patched version of Wasmtime.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
wasmtimecrates.io
< 24.0.624.0.6
wasmtimecrates.io
>= 25.0.0, < 36.0.636.0.6
wasmtimecrates.io
>= 37.0.0, < 40.0.440.0.4

Affected products

10

Patches

Vulnerability mechanics

References

10

News mentions

0

No linked articles in our index yet.