CVE-2026-49493
Arbitrary Code Execution in Markdown Preview Enhanced via Bitfield Fenced Code Blocks
Publication date: 2026-06-05
Last updated on: 2026-06-05
Assigner: VulnCheck
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| shd101wyy | markdown_preview_enhanced | to 0.8.28 (exc) |
| shd101wyy | vscode_markdown_preview_enhanced | 0.8.28 |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-94 | The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. |
Attack-Flow Graph
AI Powered Q&A
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
This vulnerability allows arbitrary code execution on the server side when rendering or exporting a crafted markdown document. Such unauthorized code execution can lead to data breaches, unauthorized access, or manipulation of sensitive information.
Because of these risks, organizations using affected versions of Markdown Preview Enhanced may face challenges in maintaining compliance with data protection standards and regulations such as GDPR and HIPAA, which require safeguarding sensitive data and preventing unauthorized system access.
Mitigating this vulnerability by updating to version 0.8.28 or later is essential to reduce the risk of non-compliance due to potential exploitation.
What immediate steps should I take to mitigate this vulnerability?
The immediate mitigation step is to upgrade Markdown Preview Enhanced to version 0.8.28 or later, where the vulnerability is fixed by replacing interpretJS() with JSON5.parse() for parsing Bitfield register definitions.
Additionally, avoid rendering or exporting markdown documents containing Bitfield fenced code blocks until the software is updated.
Can you explain this vulnerability to me?
Markdown Preview Enhanced versions before 0.8.28 have a vulnerability in how they handle Bitfield fenced code blocks. The software uses a function called interpretJS() which evaluates the content of these blocks as executable code using vm.runInNewContext(). This means that if an attacker crafts a markdown document with a malicious Bitfield code block, it can execute arbitrary code on the server when the document is rendered or exported.
The vulnerability was fixed in version 0.8.28 by changing the parsing method to JSON5.parse(), which treats the Bitfield register definitions as pure data rather than executable code, preventing arbitrary code execution.
How can this vulnerability impact me? :
This vulnerability allows an attacker to execute arbitrary code on the server hosting Markdown Preview Enhanced when it processes a malicious markdown document containing a crafted Bitfield code block. This can lead to unauthorized actions such as data theft, server compromise, or disruption of services.
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by identifying instances of Markdown Preview Enhanced software running versions prior to 0.8.28, as these versions use interpretJS() to evaluate Bitfield fenced code blocks, which is vulnerable.
To detect potential exploitation attempts, monitor for unusual or suspicious markdown documents containing Bitfield fenced code blocks being rendered or exported on your server.
Specific commands to detect the vulnerable software version or suspicious files are not provided in the available resources.