Description MyBB before 1.8.25 allows stored XSS via nested [email] tags with MyCode (aka BBCode). Remediation References CVE-2021-27279 Related Vulnerabilities PHP Insufficient Verification of Data Authenticity Vulnerability (CVE-2024-5458) Opencart Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') Vulnerability (CVE-2025-1746) MySQL Other Vulnerability (CVE-2002-1921) Apache HTTP Server Improper Link Resolution Before File Access ('Link Following') Vulnerability (CVE-2001-0131) WordPress 4.5.x Cross-Site Scripting Vulnerability (4.5 - 4.5.1) Severity Medium Classification CVE-2021-27279 CWE-707 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Tags Missing Update Known Vulnerabilities