# CVE-2026-52831: Nuclio: Unsanitized cron trigger event headers/body injected into CronJob shell command leads to persistent RCE

> Attackers can inject shell commands via cron trigger headers or body, leading to persistent remote code execution in Nuclio deployments.

- **Severity:** High 8.0 (`CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Sep 2026
- **Updated:** 3 Sep 2026
- **Also known as:** GHSA-v5px-423j-pf7p, GO-2026-5946

## What is CVE-2026-52831?

CVE-2026-52831 is a high-severity command injection vulnerability in nuclio, published on 2 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

Nuclio is a "Serverless" framework for Real-Time Events and Data Processing. Prior to version 1.16.4, the Nuclio controller builds a curl invocation string for each cron trigger and stores it as the args of a Kubernetes CronJob container (/bin/sh, -c, <command>). Two fields in the trigger specification flow into this string without adequate sanitization: event.headers keys and event.body. This issue has been patched in version 1.16.4.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2026-52831?

3 open source packages ship an affected version, including github.com/nuclio/nuclio.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/nuclio/nuclio` | Go | All versions | 0.0.0-20260601075854-3356b86a8bfa |
| `github.com/nuclio/nuclio` | Go | All versions | 0.0.0-20260601075854-3356b86a8bfa |
| `github.com/nuclio/nuclio` | Go | All versions | 0.0.0-20260601075854-3356b86a8bfa |

## How do I fix CVE-2026-52831?

Upgrade github.com/nuclio/nuclio to 0.0.0-20260601075854-3356b86a8bfa or later.

## Is CVE-2026-52831 being exploited?

There is no known exploitation of CVE-2026-52831 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-52831 and fix it if it is affected.

What it is: CVE-2026-52831 is a high-severity command injection vulnerability in nuclio, published on 2 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-52831 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/nuclio/nuclio (Go): affected all versions; fixed in 0.0.0-20260601075854-3356b86a8bfa
- github.com/nuclio/nuclio (Go): affected all versions; fixed in 0.0.0-20260601075854-3356b86a8bfa
- github.com/nuclio/nuclio (Go): affected all versions; fixed in 0.0.0-20260601075854-3356b86a8bfa

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-2026-52831/ (Markdown: https://insights.sbomify.com/CVE-2026-52831/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52831
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52831
- OSV: https://osv.dev/vulnerability/CVE-2026-52831

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52831/
Summaries are generated and may contain mistakes; the official description above is the record.