[HIGH] CVE-2026-54721 - Remote code execution via userforms email subject

PKSA-g6zg-78xs-c8r8 CVE-2026-54721 GHSA-g8wr-r2v2-vqc6

Affected version: <6.4.9|>=7.0.0,<7.0.7|>=7.1.0,<7.1.1

Reported by:
GitHub, FriendsOfPHP/security-advisories