{ "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": "2026-06-30T04:38:42.158Z" }, "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": "

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).

" } ], "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.

'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.

An 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.

This issue affects mdex: from 0.8.3 before 0.13.2.

" } ], "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 or , 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 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": "2026-06-30T04:38:42.158Z" }, "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": "

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).

" } ], "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" } } ] } }