CVE-2026-59887: Markdown-It Linkify-It

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

linkify-it is a links recognition library with full Unicode support. Prior to 5.0.2, the mailto: schema validator used by .test() and .match() can be invoked at every mailto: occurrence and scan the remaining input through src_email_name in lib/re.mjs, causing O(n^2) CPU consumption on crafted user text. This issue is fixed in version 5.0.2.

Affected products

• Markdown-It Linkify-It: before 5.0.2 (fixed in 5.0.2)

Published 2026-07-08. Last modified 2026-08-26.