Service interruption via quadratic smartquote replacements
Published Jun 17, 2026 · Updated Jun 17, 2026
Algorithmic complexity flaw in markdown-it before 14.2.0 allows remote attackers to interrupt services with quote-heavy Markdown. The smartquotes rule repeatedly calls replaceAt(), which slices and concatenates the entire token for each quote and produces quadratic processing. Exploitation requires an application to render attacker-supplied Markdown with the non-default typographer option enabled, allowing repeated inputs to exhaust CPU time.
Summary
What happened
Algorithmic complexity flaw in markdown-it before 14.2.0 allows remote attackers to interrupt services with quote-heavy Markdown. The smartquotes rule repeatedly calls replaceAt(), which slices and concatenates the entire token for each quote and produces quadratic processing. Exploitation requires an application to render attacker-supplied Markdown with the non-default typographer option enabled, allowing repeated inputs to exhaust CPU time.
The record
- CVE
- CVE-2026-48988
- Published
- Jun 17, 2026
- Updated
- Jun 17, 2026
- Vendor
- markdown-it
- Product
- markdown-it
- Classifications
- CWE-400, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 17, 2026CVE publishedPublication date reported by the CVE source.
- Jun 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 14.2.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Quote-flood rendering proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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