{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-66843", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-08-06T09:00:01.259Z", "datePublished": "2026-08-06T14:48:20.513Z", "dateUpdated": "2026-08-06T14:48:20.513Z"}, "containers": {"cna": {"affected": [{"collectionURL": "https://repo.hex.pm", "cpes": ["cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["Elixir.HtmlSanitizeEx.Scrubber.HTML5", "Elixir.HtmlSanitizeEx"], "packageName": "html_sanitize_ex", "packageURL": "pkg:hex/html_sanitize_ex", "product": "html_sanitize_ex", "programFiles": ["lib/html_sanitize_ex/scrubber/html5.ex", "lib/html_sanitize_ex.ex"], "programRoutines": [{"name": "'Elixir.HtmlSanitizeEx.Scrubber.HTML5':scrub_attribute/2"}, {"name": "'Elixir.HtmlSanitizeEx.Scrubber.HTML5':sanitize/1"}, {"name": "'Elixir.HtmlSanitizeEx':html5/1"}], "repo": "https://github.com/rrrene/html_sanitize_ex", "vendor": "rrrene", "versions": [{"lessThan": "1.5.3", "status": "affected", "version": "0.3.1", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["Elixir.HtmlSanitizeEx.Scrubber.HTML5", "Elixir.HtmlSanitizeEx"], "packageName": "rrrene/html_sanitize_ex", "packageURL": "pkg:github/rrrene/html_sanitize_ex", "product": "html_sanitize_ex", "programFiles": ["lib/html_sanitize_ex/scrubber/html5.ex", "lib/html_sanitize_ex.ex"], "programRoutines": [{"name": "'Elixir.HtmlSanitizeEx.Scrubber.HTML5':scrub_attribute/2"}, {"name": "'Elixir.HtmlSanitizeEx.Scrubber.HTML5':sanitize/1"}, {"name": "'Elixir.HtmlSanitizeEx':html5/1"}], "repo": "https://github.com/rrrene/html_sanitize_ex", "vendor": "rrrene", "versions": [{"lessThan": "bec27fec4de99e40c68c4285a610e09e791a3eaf", "status": "affected", "version": "8976d64ea0b77d26093a94a43ec48a3978e8d028", "versionType": "git"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Only <code>HtmlSanitizeEx.html5/1</code>, and custom scrubbers declared with <code>use HtmlSanitizeEx, extend: :html5</code>, allow the <code>object</code> element, and the sanitized output must be rendered to other users.</p>\n<p>Script execution in the host origin additionally requires the application to serve attacker-controlled HTML from a same-origin path, such as an uploads directory served as <code>text/html</code>.</p>"}, {"base64": false, "type": "text/markdown", "value": "Only `HtmlSanitizeEx.html5/1`, and custom scrubbers declared with `use HtmlSanitizeEx, extend: :html5`, allow the `object` element, and the sanitized output must be rendered to other users.\n\nScript execution in the host origin additionally requires the application to serve attacker-controlled HTML from a same-origin path, such as an uploads directory served as `text/html`."}], "value": "Only HtmlSanitizeEx.html5/1, and custom scrubbers declared with use HtmlSanitizeEx, extend: :html5, allow the object element, and the sanitized output must be rendered to other users.\n\nScript execution in the host origin additionally requires the application to serve attacker-controlled HTML from a same-origin path, such as an uploads directory served as text/html."}], "cpeApplicability": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:rrrene:html_sanitize_ex:*:*:*:*:*:*:*:*", "versionEndExcluding": "1.5.3", "versionStartIncluding": "0.3.1", "vulnerable": true}], "negate": false, "operator": "OR"}], "operator": "AND"}], "credits": [{"lang": "en", "type": "finder", "value": "Peter Ullrich"}, {"lang": "en", "type": "remediation developer", "value": "Ren\u00e9 F\u00f6hring"}, {"lang": "en", "type": "analyst", "value": "Jonatan M\u00e4nnchen / EEF"}], "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Inclusion of Functionality from Untrusted Control Sphere vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to load a document of their choosing into a trusted page via the <code>data</code> attribute of an <code>&lt;object&gt;</code> element in sanitized HTML. <code>object</code> is the one URI-bearing element in <code>lib/html_sanitize_ex/scrubber/html5.ex</code> never registered through <code>allow_tag_with_uri_attributes/3</code>, and its only guard is a prefix match on lowercase <code>\"javascript:\"</code>, so mixed-case variants, <code>data:</code> URIs, protocol-relative URLs and same-origin paths all survive.</p>\n<p>This is not unconditional cross-site scripting. A <code>javascript:</code> URL does not execute through <code>&lt;object data&gt;</code> in current browsers, <code>data:</code> documents load in an opaque origin, and host-origin script execution additionally requires the application to serve attacker-controlled content from a same-origin path.</p>\n<p>This issue affects html_sanitize_ex: from 0.3.1 before 1.5.3.</p>"}, {"base64": false, "type": "text/markdown", "value": "Inclusion of Functionality from Untrusted Control Sphere vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to load a document of their choosing into a trusted page via the `data` attribute of an `<object>` element in sanitized HTML. `object` is the one URI-bearing element in `lib/html_sanitize_ex/scrubber/html5.ex` never registered through `allow_tag_with_uri_attributes/3`, and its only guard is a prefix match on lowercase `\"javascript:\"`, so mixed-case variants, `data:` URIs, protocol-relative URLs and same-origin paths all survive.\n\nThis is not unconditional cross-site scripting. A `javascript:` URL does not execute through `<object data>` in current browsers, `data:` documents load in an opaque origin, and host-origin script execution additionally requires the application to serve attacker-controlled content from a same-origin path.\n\nThis issue affects html_sanitize_ex: from 0.3.1 before 1.5.3."}], "value": "Inclusion of Functionality from Untrusted Control Sphere vulnerability in the HTML5 scrubber in rrrene html_sanitize_ex allows a remote attacker to load a document of their choosing into a trusted page via the data attribute of an <object> element in sanitized HTML. object is the one URI-bearing element in lib/html_sanitize_ex/scrubber/html5.ex never registered through allow_tag_with_uri_attributes/3, and its only guard is a prefix match on lowercase \"javascript:\", so mixed-case variants, data: URIs, protocol-relative URLs and same-origin paths all survive.\n\nThis is not unconditional cross-site scripting. A javascript: URL does not execute through <object data> in current browsers, data: documents load in an opaque origin, and host-origin script execution additionally requires the application to serve attacker-controlled content from a same-origin path.\n\nThis issue affects html_sanitize_ex: from 0.3.1 before 1.5.3."}], "impacts": [{"capecId": "CAPEC-175", "descriptions": [{"lang": "en", "value": "CAPEC-175 Code Inclusion"}]}], "metrics": [{"cvssV4_0": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "baseScore": 2.3, "baseSeverity": "LOW", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "userInteraction": "PASSIVE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-829", "description": "CWE-829 Inclusion of Functionality from Untrusted Control Sphere", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-08-06T14:48:20.513Z"}, "references": [{"tags": ["vendor-advisory", "related"], "url": "https://github.com/rrrene/html_sanitize_ex/security/advisories/GHSA-xmm9-jc22-rcgj"}, {"tags": ["related"], "url": "https://cna.erlef.org/cves/CVE-2026-66843.html"}, {"tags": ["related"], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-66843"}, {"tags": ["patch"], "url": "https://github.com/rrrene/html_sanitize_ex/commit/bec27fec4de99e40c68c4285a610e09e791a3eaf"}], "source": {"discovery": "EXTERNAL"}, "title": "html_sanitize_ex HTML5 scrubber keeps attacker-supplied `<object>` elements, allowing untrusted content embedding", "workarounds": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Sanitize with <code>basic_html/1</code>, <code>markdown_html/1</code> or <code>strip_tags/1</code>, none of which allow <code>object</code>, or define a custom scrubber that omits it.</p>\n<p>A Content-Security-Policy of <code>object-src 'none'</code> blocks an injected <code>&lt;object&gt;</code> from loading, and hosting user uploads on a separate origin removes the escalation path.</p>"}, {"base64": false, "type": "text/markdown", "value": "Sanitize with `basic_html/1`, `markdown_html/1` or `strip_tags/1`, none of which allow `object`, or define a custom scrubber that omits it.\n\nA Content-Security-Policy of `object-src 'none'` blocks an injected `<object>` from loading, and hosting user uploads on a separate origin removes the escalation path."}], "value": "Sanitize with basic_html/1, markdown_html/1 or strip_tags/1, none of which allow object, or define a custom scrubber that omits it.\n\nA Content-Security-Policy of object-src 'none' blocks an injected <object> from loading, and hosting user uploads on a separate origin removes the escalation path."}]}}}

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{"created": "2026-08-06T17:00:11.048143+00:00", "updated": "2026-08-06T17:00:11.048149+00:00", "vendors": []}