CVE-2026-28499 MEDIUM

CVE-2026-28499: LeafKit's HTML escaping may be skipped for Collection values, enabling XSS

Vendor Vapor
Product leaf-kit
Weakness CWE-79 · XSS
Published March 18, 2026
Last update March 18, 2026
View on NVD All CVEs

CVSS base score

6.9/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 18, 2026 CVE published
March 18, 2026 Record updated