RCE in Shd101wyy Markdown Preview Enhanced
CVE-2026-50733
Markdown Preview Enhanced before 0.8.28 parses WaveDrom diagrams by evaluating untrusted markdown content with eval(), allowing arbitrary JavaScript execution. The flaw affects every render path - the live preview (window.eval) and presentation mode plus HTML export (the bundled WaveDrom.ProcessAll()/eva() helpers) - and can also be triggered through a <script type="WaveDrom"> element injected via raw HTML in markdown. When a victim previews or exports a crafted markdown document, an attacker can execute arbitrary code, leading to arbitrary file write. Fixed in 0.8.28 by parsing with JSON5.parse() and sanitizing WaveDrom data scripts to inert strict JSON.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (50.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Shd101wyy Markdown Preview Enhanced — versions 0
Weakness classification (CWE)
References
- github.com/shd101wyy/vscode-markdown-preview-enhanced/issues/2315 (issue-tracking)
- github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.28 (release-notes)
- www.vulncheck.com/advisories/markdown-preview-enhanced-arbitrary-code-execution… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-50733?
- CVE-2026-50733 is a high-severity vulnerability in Shd101wyy Markdown Preview Enhanced, classified under Eval Injection. CVSS score: 8.8/10. Published 2026-06-05.
- How severe is CVE-2026-50733?
- High severity. CVSS v3 base score is 8.8 out of 10.