imzbf md-editor-v3 up to 6.5.3 Highlight Callback useMarkdownIt.ts useMarkdownIt cross site scripting

Summaryinfo

A vulnerability labeled as problematic has been found in imzbf md-editor-v3 up to 6.5.3. Impacted is the function useMarkdownIt of the file packages/MdEditor/layouts/Content/composition/useMarkdownIt.ts of the component Highlight Callback. The manipulation results in cross site scripting. This vulnerability is identified as CVE-2026-84992. The attack can be executed remotely. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, was found in imzbf md-editor-v3 up to 6.5.3. Affected is the function useMarkdownIt of the file packages/MdEditor/layouts/Content/composition/useMarkdownIt.ts of the component Highlight Callback. The manipulation with an unknown input leads to a cross site scripting vulnerability. CWE is classifying the issue as CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. This is going to have an impact on integrity. CVE summarizes:

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

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-84992 since 09/02/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1059.007.

Upgrading to version 6.5.4 eliminates this vulnerability.

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Productinfo

Vendor

• imzbf

Name

• md-editor-v3

Version

• 6.5.0
• 6.5.1
• 6.5.2
• 6.5.3

Website

• Product: https://github.com/imzbf/md-editor-v3/

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