# CVE-2026-123783: Skyvern through 1.0.56 Script Sandbox Bypass via types.CodeType Bytecode


- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 6 Nov 2026
- **Updated:** 6 Nov 2026
- **Also known as:** GHSA-2555-vffj-g73c

## What is CVE-2026-123783?

CVE-2026-123783 is a high-severity vulnerability in Skyvern-AI skyvern, published on 6 Nov 2026. 

### Official description

Skyvern through 1.0.56 contains a sandbox bypass vulnerability that allows authenticated users to execute code by reconstructing functions from raw bytecode with types.CodeType. Attackers can deploy scripts that evade the is_safe_script_code AST denylist and import blocked modules such as subprocess or socket to run code in the Skyvern server process.

Weakness: CWE-184 (Incomplete List of Disallowed Inputs)

## Which versions are affected by CVE-2026-123783?


## How do I fix CVE-2026-123783?

No fix has been published for CVE-2026-123783 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-123783 being exploited?

There is no known exploitation of CVE-2026-123783 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-123783 and fix it if it is affected.

What it is: CVE-2026-123783 is a high-severity vulnerability in Skyvern-AI skyvern, published on 6 Nov 2026. 
Exploitation: There is no known exploitation of CVE-2026-123783 in the wild and no public exploit code.

Affected product: Skyvern-AI skyvern. 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-2026-123783/ (Markdown: https://insights.sbomify.com/CVE-2026-123783/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-123783
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-123783
- OSV: https://osv.dev/vulnerability/CVE-2026-123783

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-123783/
Summaries are generated and may contain mistakes; the official description above is the record.