CVE-2022-23636 Explained : Impact and Mitigation

Wasmtime, an open-source runtime for WebAssembly & WASI, was found to have a critical vulnerability prior to versions 0.34.1 and 0.33.1. This vulnerability, identified as CVE-2022-23636, could lead to an invalid drop of partially-initialized instances due to a bug in the pooling instance allocator in Wasmtime's runtime.

Understanding CVE-2022-23636

This section delves into the details of the CVE-2022-23636 vulnerability.

What is CVE-2022-23636?

CVE-2022-23636 is a vulnerability in Wasmtime that allows for an invalid drop of partially-initialized instances due to a bug in the pooling instance allocator, impacting versions prior to 0.34.1 and 0.33.1.

The Impact of CVE-2022-23636

The impact of CVE-2022-23636 is considered relatively small as it requires specific conditions to be met for exploitation. However, users are encouraged to upgrade to versions 0.34.1 or 0.33.1 as soon as possible to mitigate any potential risks.

Technical Details of CVE-2022-23636

This section provides technical insights into the CVE-2022-23636 vulnerability.

Vulnerability Description

The bug in Wasmtime's pooling instance allocator results in an invalid drop of a

VMExternRef

due to an uninitialized pointer when failing to instantiate an instance for a module with an

externref

global.

Affected Systems and Versions

Versions prior to 0.34.1 and 0.33.1 of Wasmtime are affected by CVE-2022-23636.

Exploitation Mechanism

Exploiting this vulnerability requires specific conditions as mentioned in the GitHub Security Advisory. The bug has been fixed in versions 0.34.1 and 0.33.1 of Wasmtime.

Mitigation and Prevention

Learn how to mitigate and prevent CVE-2022-23636.

Immediate Steps to Take

Users are encouraged to upgrade to versions 0.34.1 or 0.33.1 of the Wasmtime crate as soon as possible to prevent exploitation of this vulnerability.

Long-Term Security Practices

In cases where upgrading is not feasible, users can disable support for the reference types proposal by passing

false

to

Config::wasm_reference_types

to prevent loading modules using

externref

.

Patching and Updates

Ensure that the Wasmtime crate is updated to versions 0.34.1 or 0.33.1 to patch the CVE-2022-23636 vulnerability.