CVE-2021-39219 – wasmtime

Package

Manager: pip
Name: wasmtime
Vulnerable Version: >=0 <0.30.0 || >=0 <0.30.0

Severity

Level: Medium

CVSS v3.1: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:H

CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

EPSS: 0.00074 pctl0.22985

Details

Wrong type for `Linker`-define functions when used across two `Engine`s ### Impact As a Rust library the `wasmtime` crate clearly marks which functions are safe and which are `unsafe`, guaranteeing that if consumers never use `unsafe` then it should not be possible to have memory unsafety issues in their embeddings of Wasmtime. An issue was discovered in the safe API of `Linker::func_*` APIs. These APIs were previously not sound when one `Engine` was used to create the `Linker` and then a different `Engine` was used to create a `Store` and then the `Linker` was used to instantiate a module into that `Store`. Cross-`Engine` usage of functions is not supported in Wasmtime and this can result in type confusion of function pointers, resulting in being able to safely call a function with the wrong type. Triggering this bug requires using at least two `Engine` values in an embedding and then additionally using two different values with a `Linker` (one at the creation time of the `Linker` and another when instantiating a module with the `Linker`). It's expected that usage of more-than-one `Engine` in an embedding is relatively rare since an `Engine` is intended to be a globally shared resource, so the expectation is that the impact of this issue is relatively small. The fix implemented is to change this behavior to `panic!()` in Rust instead of silently allowing it. Using different `Engine` instances with a `Linker` is a programmer bug that `wasmtime` catches at runtime. ### Patches This bug has been patched and users should upgrade to Wasmtime version 0.30.0. ### Workarounds If you cannot upgrade Wasmtime and are using more than one `Engine` in your embedding it's recommended to instead use only one `Engine` for the entire program if possible. An `Engine` is designed to be a globally shared resource that is suitable to have only one for the lifetime of an entire process. If using multiple `Engine`s is required then code should be audited to ensure that `Linker` is only used with one `Engine`. ### For more information If you have any questions or comments about this advisory: * Reach out to us on [the Bytecode Alliance Zulip chat](https://bytecodealliance.zulipchat.com/#narrow/stream/217126-wasmtime) * Open an issue in [the `bytecodealliance/wasmtime` repository](https://github.com/bytecodealliance/wasmtime/)

Metadata

Created: 2021-09-20T19:54:26Z
Modified: 2024-11-19T18:05:19Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/09/GHSA-q879-9g95-56mx/GHSA-q879-9g95-56mx.json
CWE IDs: ["CWE-843"]
Alternative ID: GHSA-q879-9g95-56mx
Finding: F113
Auto approve: 1