# CVE-2026-121374: Arbitrary file write and code execution via excluded node roles in Kubernetes special agent

Status: published. Published: 2026-11-11. Updated: 2026-11-11.

Argument injection in the Kubernetes special agent in Checkmk <2.5.0p19, <2.4.0p40, and 2.3.0 (EOL) allows a user with permission to edit rules in at least one folder to write files to arbitrary locations writable by the site user via crafted node roles in the "Exclude nodes based on their role" rule option, leading to code execution as the site user.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Checkmk GmbH / Checkmk: ≥ 2.5.0; < 2.5.0p19 (affected, semver); ≥ 2.4.0; < 2.4.0p40 (affected, semver); 2.3.0 (affected, semver). Source: CNA: Checkmk

## Severity and prioritization

- CVSS 4.0: 9.4 (critical); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H; source: CNA: Checkmk

- CVSS 4.0: 9.4 (critical); CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: security@checkmk.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-88

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://checkmk.com/werk/17994 (CNA: Checkmk; vendor-advisory)

- https://checkmk.com/werk/17994 (security@checkmk.com)

## Provenance

- CNA: Checkmk: https://www.cve.org/CVERecord?id=CVE-2026-121374; retrieved 2026-11-11; source updated 2026-11-11

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-121374; retrieved 2026-11-11; source updated 2026-11-11

Revision: fb1e486088afa47e2050ee8c8cb69aaed2be276a014ae56cdf8203638096de02

Canonical: https://y2.dev/cve/CVE-2026-121374

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