---
title: "CVE-2026-52831: Nuclio: Unsanitized cron trigger event headers/body injected into CronJob shell command leads to persistent RCE"
url: https://erroneo.us/security/cve/CVE-2026-52831/
description: "CVE-2026-52831 (github.com/nuclio/nuclio (Go)): Nuclio is a \"Serverless\" framework for Real-Time Events and Data Processing. Prior to version 1.16.4, the…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-09-02
date_modified: 2026-09-03
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-52831"
kev: false
cvss: 8
epss: 0.00534
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Normal patch cycle. No exploitation signal; fix it in your next routine update if you are affected. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.5% , percentile 44: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 44% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (high (admin)). Exposure depends on who can log in.
- Only applies if your dependency tree includes github.com/nuclio/nuclio (Go) < 0.0.0-20260601075854-3356b86a8bfa, fixed in 0.0.0-20260601075854-3356b86a8bfa . Check your lockfile, including transitive dependencies.

## What it is

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, ). 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.

## Affected packages

- Go `github.com/nuclio/nuclio` < 0.0.0-20260601075854-3356b86a8bfa → fixed: 0.0.0-20260601075854-3356b86a8bfa

## Affected products (CVE record)

- nuclio nuclio: < 1.16.4

## Severity

- GitHub_M CVSS 3.1: 8 `CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 10.0 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.53% probability of exploitation activity in the next 30 days; percentile 44.

## Sources

- [GitHub Advisory GHSA-v5px-423j-pf7p](https://github.com/advisories/GHSA-v5px-423j-pf7p)
- [CVE.org record CVE-2026-52831](https://www.cve.org/CVERecord?id=CVE-2026-52831)
- [NVD entry CVE-2026-52831](https://nvd.nist.gov/vuln/detail/CVE-2026-52831)
- [github.com](https://github.com/nuclio/nuclio/security/advisories/GHSA-v5px-423j-pf7p)
- [github.com](https://github.com/nuclio/nuclio/commit/3356b86a8bfab3f960aa420310ebff765df9dede)
- [github.com](https://github.com/nuclio/nuclio/releases/tag/1.16.4)

---
Source page: https://erroneo.us/security/cve/CVE-2026-52831/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt