# CVE-2026-121374: Checkmk Kubernetes special agent argument injection

Source: https://junglewise.ai/threats/cve-2026-121374-argument-injection-in-the-kubernetes-special-agent-in-checkmk-2  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-11. Updated: 2026-11-11  
License: CC BY 4.0 with a link back

CVE-2026-121374 · Severity: info · Published 2026-11-11

Checkmk is a monitoring and infrastructure management platform. An authenticated user with rule-editing permissions can inject malicious arguments into the Kubernetes monitoring agent to write arbitrary files and execute code with the privileges of the Checkmk site user, compromising the entire monitoring infrastructure.

Technologies: [Checkmk](https://junglewise.ai/threats/technologies/checkmk). Vendors: [Checkmk](https://junglewise.ai/threats/vendors/checkmk).

## Quick answers

**Is CVE-2026-121374 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-121374 being exploited in the wild.

**How severe is CVE-2026-121374?** Informational severity, published 11 November 2026.

**Which products and versions are affected?** Checkmk 2.5.0 before 2.5.0p19, 2.4.0 before 2.4.0p40, 2.3.0 (EOL).

**Is there a fix for CVE-2026-121374?** Yes: fixed in Checkmk 2.5.0p19, 2.4.0p40, 3.0.0b1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-121374 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-121374?** Check whether you run Checkmk at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in Checkmk 2.5.0p19, 2.4.0p40, 3.0.0b1

## Technical details

The Kubernetes special agent in Checkmk fails to properly separate node role parameters from command-line options, allowing argument injection. An attacker with rule-editing permissions can craft malicious node roles (specifically using the --profile flag) to write files to arbitrary locations writable by the site user, including executable Python scripts. The vulnerability requires authentication and folder-level rule-editing permissions but does not require the target site to actually monitor Kubernetes.

## Affected products

- Checkmk Checkmk 2.5.0 before 2.5.0p19, 2.4.0 before 2.4.0p40, 2.3.0 (EOL)

## Timeline

- 2026-11-11: disclosed: CVE-2026-121374 published

## References

- [https://checkmk.com/werk/17994](https://checkmk.com/werk/17994)

## Related threats

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- [Checkmk Windows agent privilege escalation via unprotected data directory](https://junglewise.ai/threats/cve-2026-111573-incorrect-permissions-on-the-checkmk-windows-agent-s-data)
- [Checkmk Jolokia agent password exposure in process list](https://junglewise.ai/threats/cve-2026-103682-invocation-of-the-jolokia-special-agent-with-the-login-password)
- [Checkmk NetApp ONTAP password exposure in process list](https://junglewise.ai/threats/cve-2026-103674-invocation-of-the-netapp-ontap-special-agent-with-the-login)