{"id":"CVE-2026-25543","state":"PUBLISHED","title":"HtmlSanitizer has a bypass via template tag","description":"HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. Prior to versions 9.0.892 and 9.1.893-beta, if the template tag is allowed, its contents are not sanitized. The template tag is a special tag that does not usually render its contents, unless the shadowrootmode attribute is set to open or closed. This issue has been patched in versions 9.0.892 and 9.1.893-beta.","publishedAt":"2026-02-04T21:45:25.665Z","updatedAt":"2026-02-05T18:24:09.842Z","severity":{"score":6.3,"label":"Medium","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["mganss HtmlSanitizer"],"affected":[{"vendor":"mganss","product":"HtmlSanitizer","versions":[{"version":"< 9.0.892","status":"affected"},{"version":"< 9.1.893-beta","status":"affected"}]}],"references":["https://github.com/mganss/HtmlSanitizer/security/advisories/GHSA-j92c-7v7g-gj3f","https://github.com/mganss/HtmlSanitizer/commit/0ac53dca30ddad963f2b243669a5066933d82b81","https://www.nuget.org/packages/HtmlSanitizer/9.0.892","https://www.nuget.org/packages/HtmlSanitizer/9.1.893-beta"],"weaknesses":["CWE-116"],"ingestedAt":"2026-10-29T20:11:21.040Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/25xxx/CVE-2026-25543.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-25543","state":"PUBLISHED","datePublished":"2026-02-04T21:45:25.665Z","dateUpdated":"2026-02-05T18:24:09.842Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-02-02T19:59:47.375Z"},"containers":{"cna":{"title":"HtmlSanitizer has a bypass via template tag","descriptions":[{"lang":"en","value":"HtmlSanitizer is a .NET library for cleaning HTML fragments and documents from constructs that can lead to XSS attacks. Prior to versions 9.0.892 and 9.1.893-beta, if the template tag is allowed, its contents are not sanitized. The template tag is a special tag that does not usually render its contents, unless the shadowrootmode attribute is set to open or closed. This issue has been patched in versions 9.0.892 and 9.1.893-beta."}],"affected":[{"vendor":"mganss","product":"HtmlSanitizer","versions":[{"version":"< 9.0.892","status":"affected"},{"version":"< 9.1.893-beta","status":"affected"}]}],"references":[{"url":"https://github.com/mganss/HtmlSanitizer/security/advisories/GHSA-j92c-7v7g-gj3f","name":"https://github.com/mganss/HtmlSanitizer/security/advisories/GHSA-j92c-7v7g-gj3f","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/mganss/HtmlSanitizer/commit/0ac53dca30ddad963f2b243669a5066933d82b81","name":"https://github.com/mganss/HtmlSanitizer/commit/0ac53dca30ddad963f2b243669a5066933d82b81","tags":["x_refsource_MISC"]},{"url":"https://www.nuget.org/packages/HtmlSanitizer/9.0.892","name":"https://www.nuget.org/packages/HtmlSanitizer/9.0.892","tags":["x_refsource_MISC"]},{"url":"https://www.nuget.org/packages/HtmlSanitizer/9.1.893-beta","name":"https://www.nuget.org/packages/HtmlSanitizer/9.1.893-beta","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"LOW","subIntegrityImpact":"LOW","subAvailabilityImpact":"NONE","baseScore":6.3,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-116","lang":"en","description":"CWE-116: Improper Encoding or Escaping of Output","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-02-04T21:45:25.665Z"},"source":{"advisory":"GHSA-j92c-7v7g-gj3f","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-02-05T18:24:02.525697Z","id":"CVE-2026-25543","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-02-05T18:24:09.842Z"}}]}}}