Checkmk: Mehrere Schwachstellen ermöglichen Cross-Site Scripting
WID-SEC-2026-1817 · first 09.06.2026 · updated 09.06.2026 · CVSS 9,0
What it is about
Checkmk ist eine IT-Monitoring-Software. Ein entfernter, authentisierter Angreifer kann mehrere Schwachstellen in Checkmk ausnutzen, um einen Cross-Site Scripting Angriff durchzuführen.
Under what conditions?
Over the network, but only with valid access (login required), for example with stolen credentials or as an insider.
What can happen in the worst case
An attacker could use the vulnerability to
- einen Cross-Site Scripting Angriff durchzuführen
Am I affected?
Affected according to the BSI:
- Checkmk Checkmk <2.5.0p5
- Checkmk Checkmk <2.4.0p31
- Checkmk Checkmk <2.3.0p48
The installed version is usually shown under “Help → About” or in the device’s admin interface.
What helps?
Update to at least:
- Checkmk Checkmk 2.5.0p5
- Checkmk Checkmk 2.4.0p31
- Checkmk Checkmk 2.3.0p48
Is the vulnerability already being exploited?
None of the CVEs is in the CISA catalogue of exploited vulnerabilities. That does not mean there are no attacks, only that none are documented.
Information and sources
- Original BSI advisory (WID)
- CheckMK Werk 17991 vom 2026-06-08 checkmk.com
- CheckMK Werk 17992 vom 2026-06-08 checkmk.com
- CheckMK Werk 17993 vom 2026-06-08 checkmk.com
- CheckMK Werk 20002 vom 2026-06-08 checkmk.com
- CheckMK Werk 19815 vom 2026-06-08 checkmk.com
CVE: CVE-2026-7186, CVE-2026-7765, CVE-2026-8078, CVE-2026-8833, CVE-2026-9549
Source: BSI warning and information service (CERT-Bund); CISA. The assessment of the conditions is my reading of the BSI text; the external pages are in their original language.