CVE-2026-48801

What it is

linkify-it is a links recognition library with full Unicode support. Prior to 5.0.1, LinkifyIt.prototype.match, the package's primary public API, has O(N²) algorithmic complexity for inputs containing many fuzzy links or emails because the JavaScript-level scan loop re-slices input and re-runs unanchored regex searches on progressively shorter tails. Any service that synchronously renders untrusted Markdown with linkify:true on a request hot path can inherit a worker-process denial of service triggerable by a tens-of-KB request body. This issue is fixed in version 5.0.1.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-07-14 21:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-24 21:10 UTC Last updatedMost recent change to the record

Details

Published

2026-07-14 21:17 UTC

Last modified

2026-10-24 21:10 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-1333

Record status

Analyzed

Affected

• markdown-it linkify-it < 5.0.1

Attack profile CVSS 4.0 · 8.7

Attack vector

Network

Complexity

Low

Attack requirements

None

Privileges needed

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High