{"id":"CVE-2026-8833","state":"PUBLISHED","title":"XSS in urls","description":"Improper neutralization of HTML-encoded characters in the URL validation function in Checkmk <2.5.0p5, <2.4.0p31, <2.3.0p48, and all 2.2.0 versions allows an authenticated user to bypass URL validation and inject malicious URLs such as javascript: URIs, resulting in cross-site scripting when another user interacts with the crafted link.","publishedAt":"2026-06-08T12:06:51.267Z","updatedAt":"2026-06-08T13:02:45.679Z","severity":{"score":8.5,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/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":"2.5.0p5","versionType":"semver"},{"version":"2.4.0","status":"affected","lessThan":"2.4.0p31","versionType":"semver"},{"version":"2.3.0","status":"affected","lessThan":"2.3.0p48","versionType":"semver"},{"version":"2.2.0","status":"affected","versionType":"semver"}]}],"references":["https://checkmk.com/werk/20002"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/8xxx/CVE-2026-8833.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-8833","state":"PUBLISHED","datePublished":"2026-06-08T12:06:51.267Z","dateUpdated":"2026-06-08T13:02:45.679Z","assignerShortName":"Checkmk","assignerOrgId":"f7d6281c-4801-44ce-ace2-493291dedb0f","dateReserved":"2026-05-18T14:06:43.958Z"},"containers":{"cna":{"title":"XSS in urls","descriptions":[{"lang":"en","value":"Improper neutralization of HTML-encoded characters in the URL validation function in Checkmk <2.5.0p5, <2.4.0p31, <2.3.0p48, and all 2.2.0 versions allows an authenticated user to bypass URL validation and inject malicious URLs such as javascript: URIs, resulting in cross-site scripting when another user interacts with the crafted link."}],"affected":[{"vendor":"Checkmk GmbH","product":"Checkmk","defaultStatus":"unaffected","versions":[{"version":"2.5.0","status":"affected","lessThan":"2.5.0p5","versionType":"semver"},{"version":"2.4.0","status":"affected","lessThan":"2.4.0p31","versionType":"semver"},{"version":"2.3.0","status":"affected","lessThan":"2.3.0p48","versionType":"semver"},{"version":"2.2.0","status":"affected","versionType":"semver"}]}],"references":[{"url":"https://checkmk.com/werk/20002","tags":["vendor-advisory"]}],"metrics":[{"cvssV4_0":{"baseScore":8.5,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:L/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"Checkmk","orgId":"f7d6281c-4801-44ce-ace2-493291dedb0f","dateUpdated":"2026-06-08T12:06:51.267Z"},"credits":[{"lang":"en","type":"reporter","value":"Arvato Systems Offensive Security"}],"impacts":[{"capecId":"CAPEC-63","descriptions":[{"lang":"en","value":"CAPEC-63: Cross-Site Scripting (XSS)"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*","versionStartIncluding":"2.5.0","versionEndExcluding":"2.5.0p5"},{"vulnerable":true,"criteria":"cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*","versionStartIncluding":"2.4.0","versionEndExcluding":"2.4.0p31"},{"vulnerable":true,"criteria":"cpe:2.3:a:checkmk:checkmk:*:*:*:*:*:*:*:*","versionStartIncluding":"2.3.0","versionEndExcluding":"2.3.0p48"},{"vulnerable":true,"criteria":"cpe:2.3:a:checkmk:checkmk:2.2.0:*:*:*:*:*:*:*"}]}]}],"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-08T13:02:39.672018Z","id":"CVE-2026-8833","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-08T13:02:45.679Z"}}]}}}