high7.5
CVE-2026-48801
linkify-it is a links recognition library with full Unicode support.
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| npm | linkify-it | <= 5.0.0 | 5.0.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Markdown-It | Linkify-It | before 5.0.1 |