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Medium

markdown-it is has a Regular Expression Denial of Service (ReDoS)

  • Disclosed: 12.02.2026
  • Updated: 11.10.2026 10:22

Versions of the package markdown-it from 13.0.0 and before 14.1.1 are vulnerable to Regular Expression Denial of Service (ReDoS) due to the use of the regex /*+$/ in the linkify function. An attacker can supply a long sequence of * characters followed by a non-matching character, which triggers excessive backtracking and may lead to a denial-of-service condition.

Affected software

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PlatformPackageVulnerable versionsFixed in
npm package markdown-it >= 13.0.0, < 14.1.1 14.1.1

References

CVSS score 5.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness (CWE)
CWE-1333
Platform
npm
Package
markdown-it
Disclosed
12.02.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-38c4-r59v-3vqw - CC BY 4.0

Vulnerability history: markdown-it

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
8
First → latest
01.2022 10.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • High 3
  • Medium 4
  • Low 1

Disclosures per year

  1. markdown-it: Quadratic-time rendering of a single multi-line link reference definition with default options (regression since 14.0)
    High · 7.5 CVE-2026-111758 >= 14.1.0, < 14.3.3, >= 15.0.0, < 15.0.3 14.3.3, 15.0.3
  2. markdown-it: Quadratic-time denial of service in inline HTML parsing with html enabled
    Low · 3.7 CVE-2026-111766 < 14.3.3, >= 15.0.0, < 15.0.3 14.3.3, 15.0.3
  3. markdown-it: Quadratic complexity in smartquotes with unmatched closing quotes
    High · 7.5 CVE-2026-111759 >= 15.0.0, < 15.0.2, < 14.3.2 15.0.2, 14.3.2
  4. markdown-it linkify: true has two quadratic paths, so a few hundred KB of markdown blocks the event loop for tens of seconds
    Medium ghsa-253c-mchw-3w2r >= 15.0.0, < 15.0.1, < 14.3.1 15.0.1, 14.3.1
  5. markdown-it: Quadratic complexity DoS in smartquotes rule via replaceAt string operations
    Medium · 5.3 CVE-2026-48988 < 14.2.0 14.2.0
  6. markdown-it is has a Regular Expression Denial of Service (ReDoS) this entry
    Medium · 5.3 CVE-2026-2327 >= 13.0.0, < 14.1.1 14.1.1
  7. markdown-it vulnerable to Inefficient Regular Expression Complexity
    High · 7.5 CVE-2015-10005 < 3.0.0 3.0.0
  8. markdown-it < 1.3.2 - Uncontrolled Resource Consumption
    Medium · 5.3 CVE-2022-21670 < 12.3.2 12.3.2

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