CVE-2021-27946 in MyBB
Summary
by MITRE • 03/16/2021
SQL Injection vulnerability in MyBB before 1.8.26 via poll vote count. (issue 1 of 3).
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Analysis
by VulDB Data Team • 12/22/2024
The vulnerability CVE-2021-27946 represents a critical sql injection flaw discovered in MyBB versions prior to 1.8.26, specifically affecting the poll vote count functionality. This vulnerability resides within the forum software's handling of user votes in polls, where malicious actors can manipulate database queries through crafted input parameters. The issue stems from insufficient input validation and sanitization of poll vote counts, allowing attackers to inject malicious sql code that can be executed by the underlying database system. This vulnerability falls under the common weakness enumeration CWE-89 which categorizes sql injection as a serious security flaw that can lead to complete database compromise and unauthorized data access. The attack vector specifically targets the poll voting mechanism where user inputs are directly incorporated into database queries without proper escaping or parameterization.
The technical exploitation of this vulnerability occurs when users submit votes for polls, and the application fails to properly sanitize the vote count values before incorporating them into sql statements. Attackers can manipulate the poll vote count parameters to inject malicious sql payloads that bypass authentication mechanisms, extract sensitive data, modify database contents, or even execute arbitrary commands on the underlying database server. The vulnerability's impact is particularly severe because MyBB is widely used for online forums and community platforms, making it an attractive target for threat actors seeking to compromise user data and system integrity. The flaw demonstrates poor input validation practices and inadequate database query construction, creating opportunities for attackers to escalate privileges and gain unauthorized access to sensitive information including user credentials, private messages, and forum content.
The operational impact of CVE-2021-27946 extends beyond simple data theft, as it can enable complete system compromise and persistent access to affected installations. Organizations running vulnerable MyBB versions face risks of data breaches, unauthorized content modification, and potential lateral movement within their network infrastructure. The vulnerability can be exploited through standard web application attacks without requiring special privileges or advanced technical skills, making it particularly dangerous for widespread deployment. Security researchers have documented similar attack patterns in the mitre att&ck framework under the technique T1190 for exploit known vulnerabilities, highlighting how sql injection flaws can serve as initial access vectors for more sophisticated attacks. The vulnerability's presence in forum software also raises concerns about user privacy and data protection, particularly in environments where sensitive discussions occur in private forums.
Mitigation strategies for CVE-2021-27946 primarily focus on immediate software updates to MyBB version 1.8.26 or later, which contain proper input validation and sanitization measures. Organizations should implement comprehensive patch management processes to ensure all affected systems receive timely updates and verify the integrity of the patched installations. Additional defensive measures include implementing web application firewalls to detect and block suspicious sql injection attempts, conducting regular security audits of forum installations, and monitoring database logs for unusual query patterns that may indicate exploitation attempts. The vulnerability serves as a reminder of the importance of secure coding practices and proper input validation, aligning with industry standards such as the owasp top ten and iso/iec 27001 security requirements for protecting against sql injection attacks. Organizations should also consider implementing database activity monitoring solutions and regularly testing their systems for similar vulnerabilities through penetration testing and vulnerability scanning activities.