Checkmk vulnerabilities: known CVEs & security history
Checkmk · Monitoring · 10 tracked CVEs · 0 actively exploited · updated August 2026 · what is a CVE? →
This is the full list of known vulnerabilities (CVEs) across all Checkmk release lines — 10 in total. A CVE here doesn't mean your version is affected — check Checkmk's current status and the safe version to run.
Known Checkmk CVEs
Actively-exploited and most-severe first. Open any CVE for full details.
| CVE | Severity | CVSS | EPSS | Year |
|---|---|---|---|---|
| CVE-2021-40905 | high | 8.8 | 3% | 2022 |
| CVE-2021-40904 | high | 8.8 | 4% | 2022 |
| CVE-2021-40906 | medium | 6.1 | 1% | 2022 |
| CVE-2026-8833 | medium | 5.4 | 0% | 2026 |
| CVE-2026-7186 | medium | 5.4 | 0% | 2026 |
| CVE-2026-33276 | medium | 5.4 | 0% | 2026 |
| CVE-2026-20915 | medium | 5.4 | 0% | 2026 |
| CVE-2026-7765 | medium | 5.3 | 0% | 2026 |
| CVE-2026-9549 | medium | 4.8 | 0% | 2026 |
| CVE-2026-8078 | medium | 4.8 | 0% | 2026 |
Is my Checkmk version affected?
The list above spans every release. To know whether your version is affected — and the minimum safe version to upgrade to — check it directly.
Check your Checkmk version → · Monitor Checkmk for new CVEs →
Checkmk vulnerabilities — frequently asked
How many known vulnerabilities does Checkmk have?
IsItPatched tracks 10 CVEs for Checkmk. 0 are critical-severity and 2 high-severity. These span every release line — what matters is whether the version you run is affected.
Does Checkmk have any actively-exploited vulnerabilities?
None of Checkmk's tracked CVEs are currently in CISA's KEV catalog — but new ones can be added at any time, so keep your version current.
What is the most severe Checkmk vulnerability?
Among tracked issues, CVE-2021-40905 (HIGH, CVSS 8.8) ranks highest — a Unrestricted file upload weakness.
Is Checkmk safe to use?
It depends on the version. The latest supported Checkmk release (2.5) clears the known issues; older versions may still be affected. Check the exact version you run for a verdict.
CVE data aggregated from NVD, CISA KEV and EPSS (FIRST.org). Related: Checkmk security status · Checkmk end-of-life · actively-exploited CVEs. Always verify against Checkmk's advisories — see our disclaimer.