CVE-2018-6844 in MyBB
Summary
by MITRE
MyBB 1.8.14 has XSS via the Title or Description field on the Edit Forum screen.
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Analysis
by VulDB Data Team • 02/03/2021
The vulnerability identified as CVE-2018-6844 represents a cross-site scripting flaw within MyBB version 1.8.14 that specifically targets the Edit Forum screen functionality. This issue arises from inadequate input validation and output sanitization mechanisms within the forum software's administrative interface, creating a persistent security weakness that can be exploited by malicious actors to inject malicious scripts into forum metadata fields.
The technical exploitation of this vulnerability occurs through the manipulation of Title or Description fields within the Edit Forum screen where user input is not properly sanitized before being rendered back to users. When administrators or users view these forum entries, the malicious scripts contained within the unsanitized input are executed in the context of other users' browsers, potentially leading to session hijacking, credential theft, or unauthorized administrative actions. This flaw directly maps to CWE-79 which categorizes cross-site scripting vulnerabilities as weaknesses in input validation and output encoding.
The operational impact of CVE-2018-6844 extends beyond simple script execution as it can enable attackers to escalate privileges within the forum environment. An attacker who successfully exploits this vulnerability could manipulate forum content, redirect users to malicious sites, or gain unauthorized access to administrative functions. The vulnerability particularly affects forum administrators who regularly use the Edit Forum screen, making it a high-value target for attackers seeking to compromise forum integrity. The attack vector aligns with ATT&CK technique T1059.002 which covers scripting languages and T1548.001 which involves privilege escalation through valid accounts.
Mitigation strategies for this vulnerability should include immediate implementation of input sanitization measures that strip or encode potentially dangerous characters from user-supplied content before storage and rendering. The forum software should employ proper output encoding techniques when displaying forum titles and descriptions to prevent script execution. Additionally, administrators should implement strict access controls and regular security audits of forum content. The most effective remediation involves upgrading to a patched version of MyBB that properly validates and sanitizes all user input through the Edit Forum interface, following secure coding practices that prevent XSS vulnerabilities as outlined in OWASP Top Ten and NIST cybersecurity guidelines.