{"id":"CVE-2026-84992","state":"PUBLISHED","title":"md-editor-v3: XSS via fenced-code language rendering bypass","description":"md-editor-v3 is a Markdown editor for Vue 3 developed in JSX and TypeScript. Prior to 6.5.4, MdPreview's useMarkdownIt() highlight callback in packages/MdEditor/layouts/Content/composition/useMarkdownIt.ts inserts a fenced-code language value into class and language HTML attributes without escaping or consistently quoting it. Both highlighted and non-highlighted rendering paths reach this return value, while XSSPlugin filters only existing html_block and html_inline tokens before rendering and therefore cannot inspect the renderer-generated HTML. An attacker who can supply Markdown can use crafted fenced-code metadata to execute JavaScript in the application origin when a victim renders it, including as stored cross-site scripting when the host persists the Markdown. This issue is fixed in version 6.5.4","publishedAt":"2026-09-18T17:10:08.497Z","updatedAt":"2026-09-18T18:06:19.593Z","severity":{"score":6.1,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["imzbf md-editor-v3"],"affected":[{"vendor":"imzbf","product":"md-editor-v3","versions":[{"version":"< 6.5.4","status":"affected"}]}],"references":["https://github.com/imzbf/md-editor-v3/security/advisories/GHSA-3rm2-h79c-8qw6","https://github.com/imzbf/md-editor-v3/commit/2c07360420e74087f5bc63032ab155d93e0a0b10","https://github.com/imzbf/md-editor-v3/releases/tag/v6.5.4"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/84xxx/CVE-2026-84992.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-84992","state":"PUBLISHED","datePublished":"2026-09-18T17:10:08.497Z","dateUpdated":"2026-09-18T18:06:19.593Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-09-02T18:12:13.534Z"},"containers":{"cna":{"title":"md-editor-v3: XSS via fenced-code language rendering bypass","descriptions":[{"lang":"en","value":"md-editor-v3 is a Markdown editor for Vue 3 developed in JSX and TypeScript. Prior to 6.5.4, MdPreview's useMarkdownIt() highlight callback in packages/MdEditor/layouts/Content/composition/useMarkdownIt.ts inserts a fenced-code language value into class and language HTML attributes without escaping or consistently quoting it. Both highlighted and non-highlighted rendering paths reach this return value, while XSSPlugin filters only existing html_block and html_inline tokens before rendering and therefore cannot inspect the renderer-generated HTML. An attacker who can supply Markdown can use crafted fenced-code metadata to execute JavaScript in the application origin when a victim renders it, including as stored cross-site scripting when the host persists the Markdown. This issue is fixed in version 6.5.4"}],"affected":[{"vendor":"imzbf","product":"md-editor-v3","versions":[{"version":"< 6.5.4","status":"affected"}]}],"references":[{"url":"https://github.com/imzbf/md-editor-v3/security/advisories/GHSA-3rm2-h79c-8qw6","name":"https://github.com/imzbf/md-editor-v3/security/advisories/GHSA-3rm2-h79c-8qw6","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/imzbf/md-editor-v3/commit/2c07360420e74087f5bc63032ab155d93e0a0b10","name":"https://github.com/imzbf/md-editor-v3/commit/2c07360420e74087f5bc63032ab155d93e0a0b10","tags":["x_refsource_MISC"]},{"url":"https://github.com/imzbf/md-editor-v3/releases/tag/v6.5.4","name":"https://github.com/imzbf/md-editor-v3/releases/tag/v6.5.4","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":6.1,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"CHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-18T17:10:08.497Z"},"source":{"advisory":"GHSA-3rm2-h79c-8qw6","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/imzbf/md-editor-v3/security/advisories/GHSA-3rm2-h79c-8qw6","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-18T18:06:01.191667Z","id":"CVE-2026-84992","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":"2026-09-18T18:06:19.593Z"}}]}}}