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CVE PROGRAM SOURCE RECORD6.9 Medium

CVE-2026-27572

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

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Status
Published
Published
Updated
Assigning organization
GitHub_M

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

bytecodealliance wasmtime

  • < 24.0.6affected
  • >= 25.0.0, < 36.0.6affected
  • >= 37.0.0, < 40.0.4affected
  • >= 41.0.0, < 41.0.4affected

References