CVE-2026-27120

6.1 MEDIUM
Published: February 20, 2026 Modified: March 02, 2026
View on NVD

Description

Leafkit is a templating language with Swift-inspired syntax. Prior to 1.4.1, htmlEscaped in leaf-kit will only escape html special characters if the extended grapheme clusters match, which allows bypassing escaping by using an extended grapheme cluster containing both the special html character and some additional characters. In the case of html attributes, this can lead to XSS if there is a leaf variable in the attribute that is user controlled. This vulnerability is fixed in 1.4.1.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/vapor/leaf-kit/security/advisories/GHSA-4hfh-fch3-5q7p
Source: security-advisories@github.com
Exploit Vendor Advisory

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
6.1 / 10.0
EPSS (Exploit Probability)
0.0%
9th percentile
Exploitation Status
Not in CISA KEV

Affected Vendors

vapor