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CVE

CWE

Training

CVE-2026-27120

Published: Feb 20, 2026

Modified: Feb 24, 2026

PUBLISHED

CVSS v3.1

6.1

MEDIUM

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.

Vendor	Product	Versions
vapor	leaf-kit	affected `< 1.4.1`

Weaknesses (CWE)

CVSS v3.1 Details

CVSS v3.1 Vector

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

References

https://github.com/vapor/leaf-kit/security/advisories/GHSA-4hfh-fch3-5q7p

x_refsource_CONFIRM

https://github.com/vapor/leaf-kit/commit/8919e39476c3a4ba05c28b71546bb9195f87ef34

x_refsource_MISC

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