{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-54889", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-06-16T10:47:13.915Z", "datePublished": "2026-06-29T19:10:49.841Z", "dateUpdated": "2026-06-29T20:48:52.206Z"}, "containers": {"cna": {"affected": [{"collectionURL": "https://repo.hex.pm", "cpes": ["cpe:2.3:a:leandrocp:mdex:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["'Elixir.MDEx'", "'Elixir.MDEx.DeltaConverter'"], "packageName": "mdex", "packageURL": "pkg:hex/mdex", "product": "mdex", "programFiles": ["lib/mdex.ex", "lib/mdex/delta_converter.ex"], "programRoutines": [{"name": "'Elixir.MDEx':to_delta/2"}, {"name": "'Elixir.MDEx.DeltaConverter':convert/2"}, {"name": "'Elixir.MDEx.DeltaConverter':default_convert_node/3"}], "repo": "https://github.com/leandrocp/mdex", "vendor": "leandrocp", "versions": [{"lessThan": "0.13.2", "status": "affected", "version": "0.8.3", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:leandrocp:mdex:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["'Elixir.MDEx'", "'Elixir.MDEx.DeltaConverter'"], "packageName": "leandrocp/mdex", "packageURL": "pkg:github/leandrocp/mdex", "product": "mdex", "programFiles": ["lib/mdex.ex", "lib/mdex/delta_converter.ex"], "programRoutines": [{"name": "'Elixir.MDEx':to_delta/2"}, {"name": "'Elixir.MDEx.DeltaConverter':convert/2"}, {"name": "'Elixir.MDEx.DeltaConverter':default_convert_node/3"}], "repo": "https://github.com/leandrocp/mdex", "vendor": "leandrocp", "versions": [{"lessThan": "2817147f5b87ce7186aa604c9ee72499485b8f2f", "status": "affected", "version": "9852db2456fdc9d856eb636603a7f608e22e3793", "versionType": "git"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>The application must pass untrusted Markdown to <tt>'Elixir.MDEx':to_delta/2</tt> and then render the resulting Quill Delta to HTML with a renderer that maps the <tt>\"link\"</tt> and <tt>\"image\"</tt> attributes to <tt>href</tt> and <tt>src</tt> without applying its own URL scheme sanitization (for example <tt>quill-delta-to-html</tt> or the Quill client).</p>"}], "value": "The application must pass untrusted Markdown to 'Elixir.MDEx':to_delta/2 and then render the resulting Quill Delta to HTML with a renderer that maps the \"link\" and \"image\" attributes to href and src without applying its own URL scheme sanitization (for example quill-delta-to-html or the Quill client)."}], "cpeApplicability": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:leandrocp:mdex:*:*:*:*:*:*:*:*", "versionEndExcluding": "0.13.2", "versionStartIncluding": "0.8.3", "vulnerable": true}], "negate": false, "operator": "OR"}], "operator": "AND"}], "credits": [{"lang": "en", "type": "finder", "value": "Peter Ullrich"}, {"lang": "en", "type": "remediation developer", "value": "Leandro Pereira"}, {"lang": "en", "type": "analyst", "value": "Jonatan M\u00e4nnchen / EEF"}], "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in leandrocp mdex allows cross-site scripting via unsanitized URL schemes in Quill Delta output.<p><tt>'Elixir.MDEx':to_delta/2</tt> converts Markdown into a Quill Delta. <tt>'Elixir.MDEx.DeltaConverter':default_convert_node/3</tt> in <tt>lib/mdex/delta_converter.ex</tt> copies the URL of a link, wikilink, or image node directly from the parsed Markdown into the Delta <tt>\"link\"</tt> or <tt>\"image\"</tt> attribute without applying a scheme allowlist or any normalization.</p><p>An attacker who controls the Markdown text can supply a <tt>javascript:</tt> URL (for example <tt>[click](javascript:alert(document.cookie))</tt>) that survives verbatim into the Delta attribute. When the Delta is rendered to HTML by a downstream renderer (such as <tt>quill-delta-to-html</tt> or the Quill client), the attribute becomes an <tt>&lt;a href&gt;</tt> or <tt>&lt;img src&gt;</tt>, and the <tt>javascript:</tt> scheme executes in the browser of anyone who views the rendered content. The link and wikilink cases are the strongest vectors because <tt>javascript:</tt> in an <tt>href</tt> executes on click; the image case is lower impact because <tt>javascript:</tt> in <tt>&lt;img src&gt;</tt> generally does not execute in modern browsers.</p><p>This issue affects mdex: from 0.8.3 before 0.13.2.</p>"}], "value": "Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in leandrocp mdex allows cross-site scripting via unsanitized URL schemes in Quill Delta output.\n\n'Elixir.MDEx':to_delta/2 converts Markdown into a Quill Delta. 'Elixir.MDEx.DeltaConverter':default_convert_node/3 in lib/mdex/delta_converter.ex copies the URL of a link, wikilink, or image node directly from the parsed Markdown into the Delta \"link\" or \"image\" attribute without applying a scheme allowlist or any normalization.\n\nAn attacker who controls the Markdown text can supply a javascript: URL (for example [click](javascript:alert(document.cookie))) that survives verbatim into the Delta attribute. When the Delta is rendered to HTML by a downstream renderer (such as quill-delta-to-html or the Quill client), the attribute becomes an <a href> or <img src>, and the javascript: scheme executes in the browser of anyone who views the rendered content. The link and wikilink cases are the strongest vectors because javascript: in an href executes on click; the image case is lower impact because javascript: in <img src> generally does not execute in modern browsers.\n\nThis issue affects mdex: from 0.8.3 before 0.13.2."}], "impacts": [{"capecId": "CAPEC-244", "descriptions": [{"lang": "en", "value": "CAPEC-244 XSS Targeting URI Placeholders"}]}], "metrics": [{"cvssV4_0": {"attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "baseScore": 5.1, "baseSeverity": "MEDIUM", "privilegesRequired": "NONE", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "LOW", "subIntegrityImpact": "LOW", "userInteraction": "ACTIVE", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-79", "description": "CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-06-29T19:10:49.841Z"}, "references": [{"tags": ["vendor-advisory", "related"], "url": "https://github.com/leandrocp/mdex/security/advisories/GHSA-4383-7xfp-gpph"}, {"tags": ["related"], "url": "https://cna.erlef.org/cves/CVE-2026-54889.html"}, {"tags": ["related"], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-54889"}, {"tags": ["patch"], "url": "https://github.com/leandrocp/mdex/commit/2817147f5b87ce7186aa604c9ee72499485b8f2f"}], "source": {"discovery": "EXTERNAL"}, "title": "Unsanitized URL schemes in MDEx Quill Delta output allow javascript: injection (XSS)", "workarounds": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Sanitize the Quill Delta produced by <tt>'Elixir.MDEx':to_delta/2</tt> before rendering it: drop or blank any <tt>\"link\"</tt> or <tt>\"image\"</tt> value whose URL scheme is not in a safe allowlist (<tt>http</tt>, <tt>https</tt>, <tt>mailto</tt>, <tt>tel</tt>).</p>"}], "value": "Sanitize the Quill Delta produced by 'Elixir.MDEx':to_delta/2 before rendering it: drop or blank any \"link\" or \"image\" value whose URL scheme is not in a safe allowlist (http, https, mailto, tel)."}], "x_generator": {"engine": "cvelib 1.8.0"}}, "adp": [{"references": [{"url": "https://github.com/leandrocp/mdex/security/advisories/GHSA-4383-7xfp-gpph", "tags": ["exploit"]}], "metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-06-29T20:48:34.044130Z", "id": "CVE-2026-54889", "options": [{"Exploitation": "poc"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-29T20:48:52.206Z"}}]}}

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{"created": "2026-06-29T20:30:03.230542+00:00", "updated": "2026-06-29T20:30:03.230549+00:00", "vendors": []}