CVE-2026-84992: Imzbf Md-Editor-v3

Medium severity, CVSS 6.1. EPSS: 0.3% chance of exploitation in the next 30 days.

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 products

• Imzbf Md-Editor-v3: before 6.5.4 (fixed in 6.5.4)

Published 2026-09-18. Last modified 2026-09-24.