{"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 Männchen / 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":{"dateUpdated":"2026-06-29T19:10:49.841Z","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","shortName":"EEF"},"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"}}},"cveMetadata":{"assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","assignerShortName":"EEF","cveId":"CVE-2026-54889","datePublished":"2026-06-29T19:10:49.841Z","dateReserved":"2026-06-16T10:47:13.915Z","dateUpdated":"2026-06-29T19:10:49.841Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"}