CVE-2026-28499

Name: CVE-2026-28499
Creator: NVD / NIST
Published: 2026-03-18T02:16:24.06+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.9/10EPSS 0.27%

Last modified Jun 17, 2026

CVE-2026-28499 is a medium-severity vulnerability rated 6.9/10 on the CVSS scale. 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)`. EPSS estimates a 0.27% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS 4.0

6.9/10

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

EPSS Probability

0.27%

17.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Vapor	Leafkit	< 1.14.2

References

https://github.com/vapor/leaf-kit/commit/6044b844caa858a0c5f2505ac166f5a057c990dcPatch
https://github.com/vapor/leaf-kit/releases/tag/1.14.2Release Notes
https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473Exploit, Vendor Advisory
https://github.com/vapor/leaf-kit/security/advisories/GHSA-6jj5-j4j8-8473Exploit, Vendor Advisory

Timeline

Published: Mar 18, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-28499?

How severe is CVE-2026-28499?

CVE-2026-28499 has a CVSS score of 6.9/10 (MEDIUM severity). The EPSS model estimates a 0.27% probability of exploitation in the next 30 days.

How do I fix CVE-2026-28499?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-28499?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST