CVE-2026-28499: Vapor Leafkit

Medium severity, CVSS 6.1. EPSS: 0.3% chance of exploitation in the next 30 days.

LeafKit is a templating language with Swift-inspired syntax. Prior to version 1.14.2, HTML escaping doesn't work correctly when a template prints a collection (Array / Dictionary) via `#(value)`. This can result in XSS, allowing potentially untrusted input to be rendered unescaped. Version 1.14.2 fixes the issue.

Affected products

• Vapor Leafkit: before 1.14.2 (fixed in 1.14.2)

Published 2026-03-18. Last modified 2026-06-17.