# CVE-2026-114117: Vyper 0.3.8 through 0.5.0b1 Optimizer Miscompilation of msg.value | K in Ternary Branches


- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 21 Oct 2026
- **Updated:** 21 Oct 2026
- **Also known as:** GHSA-6j9c-gvcw-74fj, GHSA-xvvp-6q7c-mxwj

## What is CVE-2026-114117?

CVE-2026-114117 is a high-severity vulnerability in vyperlang vyper, published on 21 Oct 2026. 

### Official description

Vyper 0.3.8 through 0.5.0b1 contains an optimizer miscompilation in which (msg.value | K) or (len(msg.data) | K), where K is any nonzero integer literal, is compiled to the constant 1 when used as a ternary expression branch under -O gas (the default) or -O codesize. Affected contracts use the wrong value in storage writes, arithmetic, indexes, return values, or events without warning or revert, which can record deposits incorrectly and lock funds.

Weakness: CWE-682 (Incorrect Calculation)

## Which versions are affected by CVE-2026-114117?


## How do I fix CVE-2026-114117?

No fix has been published for CVE-2026-114117 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-114117 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-114117 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-114117 and fix it if it is affected.

What it is: CVE-2026-114117 is a high-severity vulnerability in vyperlang vyper, published on 21 Oct 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-114117 exists.

Affected product: vyperlang vyper. 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-2026-114117/ (Markdown: https://insights.sbomify.com/CVE-2026-114117/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-114117
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-114117
- OSV: https://osv.dev/vulnerability/CVE-2026-114117

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-114117/
Summaries are generated and may contain mistakes; the official description above is the record.