# CVE-2021-45946: Memory corruption in n/a

> An out-of-bounds write in Wasm3 allows attackers to execute arbitrary code or cause denial of service via crafted WebAssembly modules.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 31 Dec 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-4xcp-j3r2-q52p

## What is CVE-2021-45946?

CVE-2021-45946 is a medium-severity memory corruption vulnerability in n/a, published on 31 Dec 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Wasm3 0.5.0 has an out-of-bounds write in CompileBlock (called from Compile_LoopOrBlock and CompileBlockStatements).

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2021-45946?

It affects 1 product.


Products: Wasm3 Project Wasm3.

## How do I fix CVE-2021-45946?

No fix has been published for CVE-2021-45946 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-45946 being exploited?

There is no known exploitation of CVE-2021-45946 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2024-34249](https://insights.sbomify.com/CVE-2024-34249/): pywasm3 contains a heap buffer overflow which leads to segmentation fault (critical 9.8)
- [CVE-2024-27528](https://insights.sbomify.com/CVE-2024-27528/): pywasm3 has an Invalid Memory Read, Leading to DoS and Potential Code Execution (high 8.4)
- [CVE-2024-27529](https://insights.sbomify.com/CVE-2024-27529/): wasm3 uncontrolled memory allocation vulnerability (high 8.4)
- [CVE-2024-27530](https://insights.sbomify.com/CVE-2024-27530/): pywasm3 contains a Use-After-Free in ForEachModule (high 8.4)
- [CVE-2022-28990](https://insights.sbomify.com/CVE-2022-28990/): Buffer overflow in wasm3 (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-45946 and fix it if it is affected.

What it is: CVE-2021-45946 is a medium-severity memory corruption vulnerability in n/a, published on 31 Dec 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-45946 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-45946/ (Markdown: https://insights.sbomify.com/CVE-2021-45946/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-45946
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-45946
- OSV: https://osv.dev/vulnerability/CVE-2021-45946

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-45946/
Summaries are generated and may contain mistakes; the official description above is the record.