CVE-2025-29458 in MyBB
Summary
by MITRE • 04/18/2025
An issue in MyBB 1.8.38 allows a remote attacker to obtain sensitive information via the Change Avatar function.
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Analysis
by VulDB Data Team • 05/24/2025
The vulnerability identified as CVE-2025-29458 affects MyBB version 1.8.38 and represents a sensitive information disclosure flaw within the Change Avatar functionality. This issue enables remote attackers to access confidential data through a seemingly benign user interface component that should only permit avatar modifications. The vulnerability resides in the application's handling of avatar upload and processing mechanisms, where inadequate input validation and access control measures allow unauthorized data retrieval. Such a flaw demonstrates a critical weakness in the application's security architecture, particularly concerning user data protection and privilege management.
The technical implementation of this vulnerability stems from insufficient validation of user inputs during avatar processing operations. When users attempt to change their avatars through the designated interface, the system fails to properly sanitize or verify the submitted data, creating opportunities for attackers to manipulate the upload process. This weakness likely manifests through improper handling of file types, metadata extraction, or directory traversal scenarios that could expose internal system information. The flaw aligns with common security vulnerabilities categorized under CWE-200, which addresses information exposure, and may also relate to CWE-79, representing cross-site scripting vulnerabilities that could be leveraged for information gathering. The attack vector operates entirely over network communication without requiring authentication, making it particularly dangerous for widespread exploitation.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially compromise user privacy and system integrity. Attackers could exploit this flaw to access sensitive user data including but not limited to user identification information, session tokens, or potentially system configuration details that could facilitate further attacks. The remote nature of the vulnerability means that threat actors can leverage it from anywhere on the internet without requiring physical access or local system privileges. This characteristic significantly increases the attack surface and makes the vulnerability particularly attractive to automated exploitation tools. The implications for organizations using MyBB 1.8.38 include potential data breaches, compliance violations, and reputational damage resulting from unauthorized access to user information. The vulnerability also aligns with ATT&CK technique T1083, which covers file and directory discovery, as attackers could use this flaw to gather information about system structures and user data organization.
Mitigation strategies for CVE-2025-29458 should prioritize immediate patching of the affected MyBB version to address the core validation and access control issues. Organizations must implement proper input sanitization measures that validate all avatar upload parameters and enforce strict file type restrictions to prevent malicious data injection. Access controls should be strengthened to ensure that avatar processing functions properly validate user permissions and do not expose internal system information during normal operation. Network-level protections including web application firewalls and intrusion detection systems can help monitor for exploitation attempts targeting this specific vulnerability. Additionally, regular security assessments and code reviews should be conducted to identify similar issues in other application components, particularly those handling user uploads or processing external data. The implementation of proper logging and monitoring mechanisms will aid in detecting unauthorized access attempts and provide evidence for forensic analysis if exploitation occurs. Organizations should also consider implementing principle of least privilege controls to minimize the potential impact of successful exploitation attempts.