CVE-2026-28499
LeafKit's HTML escaping may be skipped for Collection values, enabling XSS
MEDIUM 6.9EPSS 0.3%
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
- vapor · leaf-kit
- CVSS v4.0 GITHUB
- 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS v4.0 GitHub
- 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 - CVSS v3.1 NVD
- 6.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N - EPSS
- 0.35% chance of exploitation in the next 30 days, 27th percentile
- Published
- 2026-03-18
Proof-of-concept exploits (1)
Security advisories
- vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473
- vapor/leaf-kit/commit/6044b844caa858a0c5f2505ac166f5a057c990dc