Inefficient Regular Expression Complexity in marked
Impact
What kind of vulnerability is it?
Denial of service.
The regular expression inline.reflinkSearch may cause catastrophic backtracking against some strings.
PoC is the following.
import * as marked from 'marked';
console.log(marked.parse(`[x]: x
\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](\\[\\](`));Who is impacted?
Anyone who runs untrusted markdown through marked and does not use a worker with a time limit.
Patches
Has the problem been patched?
Yes
What versions should users upgrade to?
4.0.10
Workarounds
Is there a way for users to fix or remediate the vulnerability without upgrading?
Do not run untrusted markdown through marked or run marked on a worker thread and set a reasonable time limit to prevent draining resources.
References
Are there any links users can visit to find out more?
- https://marked.js.org/using_advanced#workers
- 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 | < 4.0.10 | 4.0.10 |
References
- https://github.com/markedjs/marked/security/advisories/GHSA-5v2h-r2cx-5xgj
- https://nvd.nist.gov/vuln/detail/CVE-2022-21681
- https://github.com/markedjs/marked/commit/8f806573a3f6c6b7a39b8cdb66ab5ebb8d55a5f5
- https://github.com/markedjs/marked/commit/c4a3ccd344b6929afa8a1d50ac54a721e57012c0
- https://github.com/markedjs/marked
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/AIXDMC3CSHYW3YWVSQOXAWLUYQHAO5UX
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Weakness (CWE)
CWE-1333- Platform
- npm
- Package
marked- Disclosed
- 14.01.2022
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-5v2h-r2cx-5xgj - 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
-
Inefficient Regular Expression Complexity in marked this entry
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