German authorities published two security advisories for Checkmk covering multiple vulnerabilities, including flaws that could enable cross-site scripting (XSS). One advisory specifically identifies several XSS issues in the IT infrastructure and monitoring platform, while a later advisory broadens the scope to additional unspecified vulnerabilities affecting Checkmk.
The disclosures indicate that organizations using Checkmk should review vendor guidance and available patches promptly, as the vulnerabilities may expose monitoring environments to client-side code execution and other security risks. The advisories were issued by dCERT under identifiers 2026-0909 and 2026-0965, signaling an ongoing vulnerability response affecting the product.

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3 events from the most recent confirmed update back to the earliest known activity.
dCERT published advisory 2026-1029 covering multiple vulnerabilities in Checkmk. This appears to be a new follow-on disclosure in the sequence of Checkmk advisories.
dCERT later published advisory 2026-0965 concerning multiple vulnerabilities in Checkmk. The reference indicates a follow-on disclosure or update involving additional Checkmk security issues.
dCERT published advisory 2026-0909 for Checkmk, describing multiple vulnerabilities that allow cross-site scripting. This is the earliest disclosed event in the provided references.
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