markdown-it: Quadratic complexity in smartquotes with unmatched closing quotes (CVE-2026-111759)
Description
A denial of service vulnerability exists in markdown-it when the typographer option is enabled. Specially crafted Markdown input with many opening double quotes followed by unmatched closing single quotes causes quadratic processing time in the smartquotes rule. This can lead to significant delays or service disruption when processing untrusted input. The default configuration without typographer enabled is not affected. The issue is fixed in versions 15.0.2 and 14.3.2. Workarounds include disabling the typographer option or disabling the smartquotes rule.
CVSS v3.1
Score 7.5high
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
markdown-it versions >=15.0.0 <15.0.2 and <14.3.2 have a vulnerability (CVE-2026-111759) causing quadratic complexity in the smartquotes rule when typographer: true is enabled. Crafted Markdown with many opening double quotes followed by unmatched closing single quotes triggers repeated scans of the opener stack, resulting in quadratic processing time and potential denial of service. The default typographer: false configuration is unaffected. The vulnerability is patched in markdown-it 15.0.2 and 14.3.2. Disabling the smartquotes rule or the typographer option mitigates the issue.
Potential Impact
The vulnerability can cause denial of service by significantly increasing processing time when parsing malicious Markdown input with typographer enabled. This impacts availability but does not affect confidentiality or integrity. The default configuration without typographer enabled is not vulnerable. No known exploits in the wild have been reported.
Mitigation Recommendations
A fix is available in markdown-it versions 15.0.2 and 14.3.2. Users should upgrade to these versions or later. Alternatively, disable the typographer option by setting typographer: false or disable only the smartquotes rule with md.disable('smartquotes') to mitigate the vulnerability.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-r7fv-28h4-cvq7
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-111759"]
- Ecosystems
- ["npm"]
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6ad7914c2cdf04f656405af9
Added to database: 10/20/2026, 16:05:32 UTC
Last enriched: 10/20/2026, 16:18:19 UTC
Last updated: 10/20/2026, 18:48:17 UTC
Views: 7
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