{"id":"CVE-2026-100370","state":"PUBLISHED","title":"DOMSanitizer - Incomplete data: URL Sanitization in DOMSanitizer::isDangerousUrl() Allows Base64-Encoded Payloads to Bypass href and xlink:href Validation","description":"DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP 7.3+. Prior to version 1.0.15, the isDangerousUrl() method is responsible for rejecting dangerous URL values in the href and xlink:href attributes. The weakness is that \"javascript:\" is rejected as a scheme, while \"data:\" is rejected only when the literal substring onload appears in the URL value (/^data:.*onload/i). Because data: payloads are routinely Base64-encoded, the dangerous content (<script>, event handlers, etc.) is invisible to that substring test. A URL such as data:text/html;base64,… therefore survives in href / xlink:href, even though the decoded payload is active markup. This is an incomplete input-validation / sanitization defect in the sanitizer itself. This issue has been patched in version 1.0.15.","publishedAt":"2026-09-28T20:07:09.470Z","updatedAt":"2026-09-28T20:40:03.613Z","severity":{"score":4.7,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["rhukster dom-sanitizer"],"affected":[{"vendor":"rhukster","product":"dom-sanitizer","versions":[{"version":"< 1.0.15","status":"affected"}]}],"references":["https://github.com/rhukster/dom-sanitizer/security/advisories/GHSA-wcj2-r6vg-rm97","https://github.com/rhukster/dom-sanitizer/commit/10f97807e4501d60f63987f2e76a38cdbf312dcb","https://github.com/rhukster/dom-sanitizer/commit/fb8f758b41134fc5fb2f563666f2330c69e31f94","https://github.com/rhukster/dom-sanitizer/releases/tag/1.0.15"],"weaknesses":["CWE-20"],"ingestedAt":"2026-10-29T20:10:13.529Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/100xxx/CVE-2026-100370.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-100370","state":"PUBLISHED","datePublished":"2026-09-28T20:07:09.470Z","dateUpdated":"2026-09-28T20:40:03.613Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-09-25T19:19:54.699Z"},"containers":{"cna":{"title":"DOMSanitizer - Incomplete data: URL Sanitization in DOMSanitizer::isDangerousUrl() Allows Base64-Encoded Payloads to Bypass href and xlink:href Validation","descriptions":[{"lang":"en","value":"DOMSanitizer is a DOM/SVG/MathML Sanitizer for PHP 7.3+. Prior to version 1.0.15, the isDangerousUrl() method is responsible for rejecting dangerous URL values in the href and xlink:href attributes. The weakness is that \"javascript:\" is rejected as a scheme, while \"data:\" is rejected only when the literal substring onload appears in the URL value (/^data:.*onload/i). Because data: payloads are routinely Base64-encoded, the dangerous content (<script>, event handlers, etc.) is invisible to that substring test. A URL such as data:text/html;base64,… therefore survives in href / xlink:href, even though the decoded payload is active markup. This is an incomplete input-validation / sanitization defect in the sanitizer itself. This issue has been patched in version 1.0.15."}],"affected":[{"vendor":"rhukster","product":"dom-sanitizer","versions":[{"version":"< 1.0.15","status":"affected"}]}],"references":[{"url":"https://github.com/rhukster/dom-sanitizer/security/advisories/GHSA-wcj2-r6vg-rm97","name":"https://github.com/rhukster/dom-sanitizer/security/advisories/GHSA-wcj2-r6vg-rm97","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/rhukster/dom-sanitizer/commit/10f97807e4501d60f63987f2e76a38cdbf312dcb","name":"https://github.com/rhukster/dom-sanitizer/commit/10f97807e4501d60f63987f2e76a38cdbf312dcb","tags":["x_refsource_MISC"]},{"url":"https://github.com/rhukster/dom-sanitizer/commit/fb8f758b41134fc5fb2f563666f2330c69e31f94","name":"https://github.com/rhukster/dom-sanitizer/commit/fb8f758b41134fc5fb2f563666f2330c69e31f94","tags":["x_refsource_MISC"]},{"url":"https://github.com/rhukster/dom-sanitizer/releases/tag/1.0.15","name":"https://github.com/rhukster/dom-sanitizer/releases/tag/1.0.15","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":4.7,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-20","lang":"en","description":"CWE-20: Improper Input Validation","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-28T20:07:09.470Z"},"source":{"advisory":"GHSA-wcj2-r6vg-rm97","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/rhukster/dom-sanitizer/security/advisories/GHSA-wcj2-r6vg-rm97","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-28T20:39:56.823996Z","id":"CVE-2026-100370","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-28T20:40:03.613Z"}}]}}}