# CVE-2026-29514: NetBox 4.3.5 - 4.5.4 RCE via RenderTemplateMixin

> Authenticated users with template permissions can execute arbitrary code by injecting malicious Python callables into environment parameters, bypassing sandbox restrictions.

- **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
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 May 2026
- **Updated:** 14 Jul 2026
- **Also known as:** GHSA-f249-4qx6-hg68

## What is CVE-2026-29514?

CVE-2026-29514 is a high-severity code injection vulnerability in netbox-community netbox, published on 4 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

NetBox versions 4.3.5 through 4.5.4 contain a remote code execution vulnerability in the RenderTemplateMixin.get_environment_params() method that allows authenticated users with exporttemplate or configtemplate permissions to execute arbitrary code by specifying malicious Python callables in the environment_params field. Attackers can bypass Jinja2 SandboxedEnvironment protections by setting the finalize parameter to any importable Python callable such as subprocess.getoutput, which is invoked on every rendered expression outside the sandbox's call interception mechanism, achieving remote code execution as the NetBox service user.

Weakness: CWE-183 (Permissive List of Allowed Inputs)

## Which versions are affected by CVE-2026-29514?


## How do I fix CVE-2026-29514?

No fix has been published for CVE-2026-29514 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-29514 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-29514 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-29514 and fix it if it is affected.

What it is: CVE-2026-29514 is a high-severity code injection vulnerability in netbox-community netbox, published on 4 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-29514 exists.

Affected product: netbox-community netbox. 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-2026-29514/ (Markdown: https://insights.sbomify.com/CVE-2026-29514/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-29514
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-29514
- OSV: https://osv.dev/vulnerability/CVE-2026-29514

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-29514/
Summaries are generated and may contain mistakes; the official description above is the record.