CVE-2026-59887 HIGH

CVE-2026-59887: linkify-it: Quadratic-complexity DoS via the `mailto:` validator scan-loop on attacker text

Vendor Markdown-It
Product linkify-it
Weakness CWE-407
Published July 8, 2026
Last update July 9, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

July 8, 2026 CVE published
July 9, 2026 Record updated