Description Cross-site Scripting (XSS) vulnerability in MyBB before 1.8.26 via Nested Auto URL when parsing messages. Remediation References CVE-2021-27889 Related Vulnerabilities IBM RTC Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') Vulnerability (CVE-2016-2986) WordPress Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') Vulnerability (CVE-2019-16219) WordPress Plugin File Manager Unspecified Vulnerability (4.1.4) WordPress Plugin YITH WooCommerce Ajax Search Security Bypass (1.6.9) ATutor Improper Privilege Management Vulnerability (CVE-2017-1000003) Severity Medium Classification CVE-2021-27889 CWE-707 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Tags Missing Update Known Vulnerabilities