CVEvulnerability

CVE-2026-27120

6.1 MEDIUM Published 2026-02-20 Modified 2026-06-17 Official page ↗

Status: Analyzed
Published: 2026-02-20
Last modified: 2026-06-17
Assigner: [email protected]
CVSS 3.1 ([email protected]): 6.1 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weaknesses: CWE-75, CWE-79, CWE-87

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.

Affected configurations

• vapor leafkit (< 1.14.1)

Weakness · CWE (3)

CWE-75 Failure to Sanitize Special Elements into a Different Plane weakness
CWE-79 Improper Neutralization of Input During Web Page Generation weakness
CWE-87 Improper Neutralization of Alternate XSS Syntax weakness

References

https://github.com/vapor/leaf-kit/commit/8919e39476c3a4ba05c28b71546bb9195f87ef34 Patch
https://github.com/vapor/leaf-kit/security/advisories/GHSA-4hfh-fch3-5q7p Exploit, Vendor Advisory

CVE-2026-27120

Description

Affected configurations

Related

Weakness · CWE (3)

References