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High 8.4Published Oct 30, 2025
CVE-2025-39663Cross-Site Scripting (XSS) vulnerability in Checkmk's distributed monitoring allows a compromised remote site to inject malicious HTML code into service outputs in the central site.
Updated under an hour ago ()
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Cross-Site Scripting (XSS) vulnerability in Checkmk's distributed monitoring allows a compromised remote site to inject malicious HTML code into service outputs in the central site. Affecting Checkmk before 2.4.0p14, 2.3.0p39, 2.2.0 and 2.1.0 (eol).
- CVSS
- 8.4 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H
- Weakness (CWE)
- CWE-80, CWE-79
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jun 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
checkmk checkmk checkmk:checkmk | from 2.0.0 before 2.3.0; 2.3.0; 2.3.0; 2.3.0; 2.3.0; 2.3.0; 2.3.0; 2.3.0; and 45 more ranges | NVD |
References
- https://checkmk.com/werk/17998vendor-advisory
- https://github.com/sbaresearch/advisories/tree/82fd27e4570433464c30b35150b197db9a850f4e/2025/SBA-ADV-20250729-01_Checkmk_Cross_Site_Scriptingexploit, third-party-advisory
- http://seclists.org/fulldisclosure/2025/Nov/0exploit, mailing-list, third-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.