Vulnerability Description
markdown-it is a Markdown parser. Versions 14.1.1 and below contain a denial-of-service vulnerability when typographer: true is enabled, due to quadratic (O(n^2)) processing in the smartquotes rule. The issue stems from repeatedly modifying strings with replaceAt(), which performs O(n) slicing and concatenation per quote character. This can cause excessive CPU consumption when parsing quote-heavy, user-supplied markdown and may let attackers degrade or disrupt service availability. Although typographer is disabled by default, many production apps enable it for smart typography, making the issue relevant. This issue has been fixed in version 14.2.0.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Markdown-It Project | Markdown-It | < 14.2.0 |
Related Weaknesses (CWE)
References
- https://github.com/markdown-it/markdown-it/commit/9ce2087562c45d1e5ddd9f76b990f4Patch
- https://github.com/markdown-it/markdown-it/security/advisories/GHSA-6v5v-wf23-fmExploitMitigationVendor Advisory
- https://github.com/markdown-it/markdown-it/security/advisories/GHSA-6v5v-wf23-fmExploitMitigationVendor Advisory
FAQ
What is CVE-2026-48988?
CVE-2026-48988 is a vulnerability with a CVSS score of 5.3 (MEDIUM). markdown-it is a Markdown parser. Versions 14.1.1 and below contain a denial-of-service vulnerability when typographer: true is enabled, due to quadratic (O(n^2)) processing in the smartquotes rule. T...
How severe is CVE-2026-48988?
CVE-2026-48988 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-48988?
Check the references section above for vendor advisories and patch information. Affected products include: Markdown-It Project Markdown-It.