Description
markdown-it is a Markdown parser. Prior to 14.3.2 and 15.0.2, when typographer: true is enabled, specially crafted Markdown can cause quadratic processing time in the smartquotes rule, potentially leading to denial of service in applications processing untrusted input. Many opening double quotes followed by unmatched closing single quotes cause repeated scans of the entire opener stack. The same issue occurs with the quote types reversed. The default configuration (typographer: false) is not affected, but this option is enabled with high probability. This issue is fixed in versions 14.3.2 and 15.0.2.
References7
- github.com/markdown-it/markdown-it/commit/1b379c1b6d0522421bd1a…
- github.com/markdown-it/markdown-it/commit/cf27366035edf91966671…
- github.com/markdown-it/markdown-it/commit/daf5a3c32303e5d9de01b…
- github.com/markdown-it/markdown-it/releases/tag/14.3.2
- github.com/markdown-it/markdown-it/releases/tag/15.0.2
- github.com/markdown-it/markdown-it/security/advisories/GHSA-r7f…
- github.com/markdown-it/markdown-it/security/advisories/GHSA-r7f…
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 49 · as of 10 November 2026
- CWE
- CWE-400CWE-407
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.