CVE-2026-28499

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

Published: Mar 18, 2026Updated: Mar 18, 2026 Sources: CVE List NVD GHSACWE-79

6.1MEDIUM

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:RUser Interaction

Required

Scope

S:CScope

Changed

Impact

C:LConfidentiality

Low

I:LIntegrity

Low

A:NAvailability

None

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Weaknesses

CWE-79 CWE-80 CWE-116

Affected Products

vapor

oss-projectaka vapor swift framework

leafkitMixed

OSS Libraries / web-framework

leaf-kitMixed

OSS Libraries / web-framework

SwiftURL

aka swift-nio-http2, github.com/vapor/vapor, github.com/apple/swift-nio-http2, github.com/pytorch/executorch

github.com/vapor/leaf-kitLibrary

OSS Libraries / generic-library

Exploitability

Official Patch Available

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques

Execution

Initial Access

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References

https://github.com/vapor/leaf-kit/commit/6044b844caa858a0c5f2505ac166f5a057c990dc

github.com

https://github.com/vapor/leaf-kit/releases/tag/1.14.2

github.com

https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473

github.com

and 2 more references View all →

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