CVE-2021-48020 Vyper before 0.3.0 Memory Corruption via Internal Function Calls in Arrays
High 8.3
Published
Updated
Check this codebase for CVE-2021-48020 and fix it if it is affected.
What it is: CVE-2021-48020 is a high-severity vulnerability in vyperlang vyper, published on 21 Oct 2026.
Exploitation: There is no known exploitation of CVE-2021-48020 in the wild and no public exploit code.
Affected packages and fixed versions:
- vyper (PyPI): affected all versions; fixed in 0.2.12
- vyper (PyPI): affected all versions; fixed in 0.2.12
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-2021-48020/ (Markdown: https://insights.sbomify.com/CVE-2021-48020/index.md)
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2021-48020?
CVE-2021-48020 is a high-severity vulnerability in vyperlang vyper, published on 21 Oct 2026.
Official description
Vyper from 0.1.0b4 before 0.3.0 contains a memory corruption vulnerability caused by an incorrect stack tip pointer when internal function calls are performed inside arrays. Contracts placing internal calls in nested array elements, external call arguments, struct literals, or raw_log topics can have memory corrupted, producing incorrect contract behavior.
Weakness: CWE-787
Which versions are affected by CVE-2021-48020?
2 open source packages ship an affected version, including vyper.
| Package | Affected | Fixed in |
|---|---|---|
vyper PyPI | All versions | 0.2.12 |
vyper PyPI | All versions | 0.2.12 |
How do I fix CVE-2021-48020?
Upgrade vyper to 0.2.12 or later.
Is CVE-2021-48020 being exploited?
There is no known exploitation of CVE-2021-48020 in the wild and no public exploit code.
Sources
Also known as GHSA-22wc-c9wj-6q2v, GHSA-vq78-2j7f-9gqx.