CVE-2026-84992md-editor-v3: XSS via fenced-code language rendering bypass
- 6.1MediumCVSS base score
- 0.33%Exploitation in 30 daysEPSS · top 74% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
- https://github.com/imzbf/md-editor-v3/security/advisories/GHSA-3rm2-h79c-8qw6 (opens in a new tab)x_refsource_CONFIRMexploit
Timeline
ID reserved
By GitHub_M
- 16 days later
· 16 days later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVDNVD · Deferred | 3.1 | Medium6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.33% · top 74% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.1.
Affected products
- affected < 6.5.4
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- npmmd-editor-v3GHSA-3rm2-h79c-8qw6 (opens in a new tab)
References
References3
- https://github.com/imzbf/md-editor-v3/security/advisories/GHSA-3rm2-h79c-8qw6 (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/imzbf/md-editor-v3/commit/2c07360420e74087f5bc63032ab155d93e0a0b10 (opens in a new tab)x_refsource_MISC
- https://github.com/imzbf/md-editor-v3/releases/tag/v6.5.4 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-83198 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-3rm2-h79c-8qw6 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-84992)Record last updated .