Overview
A critical vulnerability, CVE-2025-29457, has been identified in MyBB 1.8.38, a widely used open-source forum software. This vulnerability allows a remote attacker to potentially gain unauthorized access to sensitive information through the Import a Theme function. It is crucial to address this vulnerability as it could lead to system compromise and data leakage, impacting the confidentiality and integrity of the data.
Vulnerability Summary
CVE ID: CVE-2025-29457
Severity: High (7.6)
Attack Vector: Network
Privileges Required: None
User Interaction: Required
Impact: Potential system compromise and data leakage
Affected Products
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Product | Affected Versions
MyBB | 1.8.38
How the Exploit Works
The vulnerability stems from the improper handling of the Import a Theme function in MyBB 1.8.38. A remote attacker can manipulate the function to extract sensitive information. While the exact method of exploitation is unknown, it typically involves crafting a malicious payload that, when processed by the Import a Theme function, allows the attacker to obtain sensitive data.
Conceptual Example Code
The code below is a conceptual example of how the vulnerability might be exploited:
POST /mybb/admin/index.php?module=style-themes&action=import HTTP/1.1
Host: target.example.com
Content-Type: application/xml
<theme name="malicious_theme" xmlns="http://www.mybb.com/">
<properties>
<!-- malicious payload here -->
</properties>
</theme>In this example, the attacker sends a malicious XML theme to the import function. The malicious payload embedded in the theme properties can then cause the application to disclose sensitive information.
Mitigation Guidance
Users are advised to apply the vendor patch as soon as it becomes available. In the meantime, deploying a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) could serve as temporary mitigation against this vulnerability.
