CVE-2021-39219
6.3 · MEDIUMOverview
CVE-2021-39219 is a medium-severity vulnerability affecting bytecodealliance wasmtime. It was published on September 17, 2021 and has a CVSS 3.1 base score of 6.3 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.3, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
Technical Description
Wasmtime is an open source runtime for WebAssembly & WASI. Wasmtime before version 0.30.0 is affected by a type confusion vulnerability. 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
Remediation
Check the references section for vendor advisories and patches from bytecodealliance. Update wasmtime to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| bytecodealliance | wasmtime | >= 0, < 0.30.0 | Affected |
References
Frequently Asked Questions
What is CVE-2021-39219?
CVE-2021-39219 is a medium-severity vulnerability affecting bytecodealliance wasmtime. It was published on September 17, 2021 and has a CVSS 3.1 base score of 6.3 (MEDIUM).
How severe is CVE-2021-39219?
This vulnerability has a CVSS 3.1 base score of 6.3, rated MEDIUM. It requires local or adjacent network access to exploit. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-39219?
Check the references section for vendor advisories and patches from bytecodealliance. Update wasmtime to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-39219?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-39219 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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