{"id":"CVE-2026-15576","title":"Improper authentication in the agent receiver of Checkmk <2.5.0p10 allows an unauthenticated remote attacker to bypass mutual TLS client certificate verification of relay endpoints by supplying a fixed placeholder identity in the request…","summary":"Improper authentication in the agent receiver of Checkmk <2.5.0p10 allows an unauthenticated remote attacker to bypass mutual TLS client certificate verification of relay endpoints by supplying a fixed placeholder identity in the request…","severity":"none","cwe":["CWE-306"],"published":"2026-08-21","updated":"2026-10-16","sourceUpdated":"2026-10-16T15:10:00.103","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-15576","references":[{"url":"https://checkmk.com/werk/20174","label":"security@checkmk.com"}],"tags":["nvd"],"epss":0.00453,"epssPercentile":0.39145,"ingestedAt":"2026-10-27T18:52:09.906Z","slug":"CVE-2026-15576","body":"## Overview\n\nImproper authentication in the agent receiver of Checkmk <2.5.0p10 allows an unauthenticated remote attacker to bypass mutual TLS client certificate verification of relay endpoints by supplying a fixed placeholder identity in the request URL, resulting in limited impact on integrity and availability. Only the Cloud, Ultimate and Ultimate MT editions are affected, as other editions do not expose relay endpoints.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}