{"items":[{"id":"NVI-00013942","kind":"vulnerability","title":"md-editor-v3: XSS via fenced-code language rendering bypass","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-3rm2-h79c-8qw6","CVE-2026-84992"],"plain_summary":"GitHub lists this reviewed advisory for md-editor-v3. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-218b80cbc2be69a5881dab0c862bb6ad"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-09-18T17:17:38.000Z","value":"6.1 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-218b80cbc2be69a5881dab0c862bb6ad"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-218b80cbc2be69a5881dab0c862bb6ad","url":"https://github.com/advisories/GHSA-3rm2-h79c-8qw6","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-3rm2-h79c-8qw6","publisher":"GitHub Advisory Database","observed_at":"2026-11-01T14:29:49.409Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-218b80cbc2be69a5881dab0c862bb6ad"],"technology":"md-editor-v3","known_exclusions":[],"conditions_summary":"### Summary\n`MdPreview` interpolates a fenced-code language into HTML attributes without escaping it. A crafted info string therefore executes JavaScript even when the shipped `XSSPlugin` is enabled.\n\n### Details\n`useMarkdownIt()` (`packages/MdEditor/layouts/Content/composition/useMarkdownIt.ts:206`) registers a `highlight` callback whose final return inserts `language` into both `class=\"language-${language}\"` and an unquoted `language=${language}` attribute without escaping. Both highlighting paths reach this return. `XSSPlugin()` filters only existing `html_block` and `html_inline` tokens before rendering, so it cannot inspect this renderer-generated HTML.\n\n### PoC\nThe Vue application enables the shipped `XSSPlugin` and renders attacker-controlled Markdown. `noHighlight: true` only makes reproduction deterministic; the default highlighting path reaches the same unsafe return. Use this as `src/main.js`:\n\n```js\nimport { createApp, h } from 'vue';\nimport { MdPreview, XSSPlugin, config } from 'md-editor-v3';\n\nconfig({ markdownItPlugins: p => [...p, { type: 'xss', plugin: XSSPlugin, options: {} }] });\nconst markdown = '```x\">\\nSAFE\\n```';\n","public_affected_ranges":["<= 6.5.3"]}],"null_published_at":"2026-11-02T10:00:37.177Z","source_updated_at":"2026-09-18T17:17:38.000Z","source_disclosed_at":"2026-09-18T17:17:36.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-11-01T14:29:49.409Z"}],"next_cursor":null,"snapshot_revision":"42594"}