CVE-2011-5278 in Advanced Forum Signatures
Summary
by MITRE
SQL injection vulnerability in signature.php in Advanced Forum Signatures plugin (aka afsignatures) 2.0.4 for MyBB allows remote attackers to execute arbitrary SQL commands via the afs_bar_right parameter.
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Analysis
by VulDB Data Team • 05/09/2026
The CVE-2011-5278 vulnerability represents a critical sql injection flaw within the Advanced Forum Signatures plugin version 2.0.4 for MyBB bulletin board systems. This vulnerability specifically targets the signature.php script and affects the afs_bar_right parameter, creating a pathway for remote attackers to execute arbitrary sql commands against the underlying database. The issue stems from inadequate input validation and sanitization within the plugin's parameter handling mechanism, allowing malicious actors to inject sql payloads through the web interface.
The technical exploitation of this vulnerability occurs when user input containing sql commands is directly incorporated into sql queries without proper escaping or parameterization. The afs_bar_right parameter serves as the attack vector where unvalidated user input gets processed and subsequently used in database operations. This creates a classic sql injection scenario where attackers can manipulate the sql execution flow to extract, modify, or delete database contents. The vulnerability is particularly dangerous because it operates at the database level, potentially allowing full compromise of the forum's data integrity and confidentiality.
From an operational impact perspective, this vulnerability exposes organizations running affected MyBB installations to significant risks including data breaches, unauthorized access to user accounts, and potential system compromise. Attackers could leverage this flaw to extract sensitive user information such as usernames, passwords, and private messages stored in the database. The vulnerability also enables privilege escalation attacks where malicious users might gain administrative access to the forum system, leading to complete system takeover. Additionally, the compromise could result in denial of service conditions or data corruption that affects the entire forum infrastructure.
The vulnerability aligns with CWE-89 which specifically addresses sql injection flaws in software systems. From an attacker methodology standpoint, this vulnerability maps to several ATT&CK techniques including T1190 for exploitation of vulnerabilities and T1071.004 for application layer protocols. The attack chain typically involves reconnaissance to identify the vulnerable plugin version, crafting malicious payloads targeting the afs_bar_right parameter, and executing sql commands to achieve desired outcomes. Organizations should prioritize immediate patching of the affected plugin version and implement input validation measures to prevent similar issues in other components of their web applications.
Mitigation strategies should include immediate deployment of the vendor-provided security patches for the Advanced Forum Signatures plugin, followed by comprehensive security audits of all installed plugins and themes. Organizations should implement web application firewalls to detect and block sql injection attempts, establish proper input validation routines, and conduct regular vulnerability assessments. Additionally, database access controls should be reviewed to ensure least privilege principles are enforced, and all user inputs should be properly escaped or parameterized before database interaction. Network segmentation and monitoring solutions should be deployed to detect anomalous database access patterns that may indicate exploitation attempts.