CVE-2026-42548 HIGH

CVE-2026-42548: Flight: Reflected XSS via unvalidated JSONP callback in Flight::jsonp()

Vendor Flightphp
Product core
Weakness CWE-79 · XSS
Published May 13, 2026
Last update May 14, 2026

CVSS base score

8.6/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:N/SC:L/SI:L/SA:N

What the vulnerability does

01Description

Flight is an extensible micro-framework for PHP. Prior to 3.18.1, Flight::jsonp() concatenates the ?jsonp= query parameter directly into an application/javascript response body without validating that the value is a legal JavaScript identifier. An attacker can inject arbitrary JavaScript that executes in the response origin, enabling reflected cross-site scripting. This vulnerability is fixed in 3.18.1.

Key dates

02Disclosure timeline

May 13, 2026 CVE published
May 14, 2026 Record updated