CVE-2026-28499

LeafKit's HTML escaping may be skipped for Collection values, enabling XSS

State: Published
Severity: 6.9 Medium
Published: Mar 18, 2026
Updated: Mar 18, 2026
Reserved: Feb 27, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	6.9 Medium	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	GitHub_M

Weaknesses

CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-80 Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)
CWE-116 Improper Encoding or Escaping of Output

Affected Products

Product	Versions
leaf-kitvapor	< 1.14.2Affected

References

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