Regular Expression Denial of Service (REDoS) in Marked
Impact
What kind of vulnerability is it? Who is impacted?
Regular expression Denial of Service
A Denial of Service attack can affect anyone who runs user generated code through marked.
Patches
Has the problem been patched? What versions should users upgrade to?
patched in v2.0.0
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
None.
References
Are there any links users can visit to find out more?
https://github.com/markedjs/marked/issues/1927 https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS
For more information
If you have any questions or comments about this advisory:
- Open an issue in marked
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | marked | >= 1.1.1, < 2.0.0 | 2.0.0 |
References
- https://github.com/markedjs/marked/security/advisories/GHSA-4r62-v4vq-hr96
- https://nvd.nist.gov/vuln/detail/CVE-2021-21306
- 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
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- Weakness (CWE)
CWE-400- Platform
- npm
- Package
marked- Disclosed
- 08.02.2021
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-4r62-v4vq-hr96 - CC BY 4.0
Vulnerability history: marked
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 13
- First → latest
- 10.2017 04.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 5
- Medium 7
- Low 1
Disclosures per year
- 2017: 2
- 2018: 2
- 2019: 2
- 2020: 2
- 2021: 1
- 2022: 2
- 2023: 0
- 2024: 0
- 2025: 1
- 2026: 1
-
Regular Expression Denial of Service (REDoS) in Marked this entry
Know which vulnerabilities affect your application
With the DockRay integration and software inventory enabled, DockRay checks reported component versions against known vulnerabilities and notifies you about confirmed matches. Coverage depends on the supported technology and available advisory data.