{"id":"CVE-2026-15937","state":"PUBLISHED","title":"Agent receiver certificate confusion allows authentication with a certificate issued for another endpoint","description":"Improper certificate validation in Checkmk <2.5.0p10 allows a relay and a push agent that share the same UUID to reuse each other's mTLS certificate to authenticate against agent receiver endpoints in either direction, because the endpoints do not verify that the certificate was issued by their own root certificate.","publishedAt":"2026-09-04T08:24:49.802Z","updatedAt":"2026-09-04T19:39:28.278Z","severity":{"score":5.3,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","source":"Checkmk"},"assigner":"Checkmk","products":["Checkmk GmbH Checkmk"],"affected":[{"vendor":"Checkmk GmbH","product":"Checkmk","defaultStatus":"unaffected","versions":[{"version":"2.5.0","status":"affected","lessThan":"2.5.0p10","versionType":"semver"}]}],"references":["https://checkmk.com/werk/19735"],"weaknesses":["CWE-295"],"ingestedAt":"2026-10-29T20:11:00.674Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/15xxx/CVE-2026-15937.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-15937","state":"PUBLISHED","datePublished":"2026-09-04T08:24:49.802Z","dateUpdated":"2026-09-04T19:39:28.278Z","assignerShortName":"Checkmk","assignerOrgId":"f7d6281c-4801-44ce-ace2-493291dedb0f","dateReserved":"2026-07-16T08:40:57.255Z"},"containers":{"cna":{"title":"Agent receiver certificate confusion allows authentication with a certificate issued for another endpoint","descriptions":[{"lang":"en","value":"Improper certificate validation in Checkmk <2.5.0p10 allows a relay and a push agent that share the same UUID to reuse each other's mTLS certificate to authenticate against agent receiver endpoints in either direction, because the endpoints do not verify that the certificate was issued by their own root certificate."}],"affected":[{"vendor":"Checkmk GmbH","product":"Checkmk","defaultStatus":"unaffected","versions":[{"version":"2.5.0","status":"affected","lessThan":"2.5.0p10","versionType":"semver"}]}],"references":[{"url":"https://checkmk.com/werk/19735","tags":["vendor-advisory"]}],"metrics":[{"cvssV4_0":{"baseScore":5.3,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-295","description":"CWE-295: Improper Certificate Validation","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"Checkmk","orgId":"f7d6281c-4801-44ce-ace2-493291dedb0f","dateUpdated":"2026-09-04T08:24:49.802Z"},"credits":[{"lang":"en","type":"reporter","value":"PS Positive Security GmbH"}],"impacts":[{"capecId":"CAPEC-114","descriptions":[{"lang":"en","value":"CAPEC-114: Authentication Abuse"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*","versionStartIncluding":"2.5.0","versionEndExcluding":"2.5.0p10"}]}]}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-04T19:39:13.186762Z","id":"CVE-2026-15937","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-04T19:39:28.278Z"}}]}}}