CVE-2026-50733

Markdown Preview Enhanced Arbitrary Code Execution via WaveDrom eval()

HIGH
8.8
CVSS Score
Published: June 5, 2026 at 05:49 PM UTC
Updated: October 26, 2026 at 11:10 AM UTC
2 products affected across 2 vendorsMarkdown Preview EnhancedMarkdown Preview Enhanced

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Severity
HIGH8.8
Exploit prediction
EPSS 0.7%
SSVC
PoC

Description

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.8.28
Affected range stops below 0.8.28, so it looks safe — our inference, not a vendor statement
v < 0.8.28
Affected range stops below 0.8.28, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-95

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