Overview
The vulnerability identified as CVE-2025-29458 is a critical issue found in MyBB 1.8.38 that allows a remote attacker to obtain sensitive information via the Change Avatar function. This vulnerability poses significant risks to MyBB forum administrators and users, as it may potentially lead to system compromises or data leakage.
Vulnerability Summary
CVE ID: CVE-2025-29458
Severity: High (7.6/10)
Attack Vector: Network
Privileges Required: Low
User Interaction: Required
Impact: Possible system compromise and data leakage
Affected Products
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Product | Affected Versions
MyBB | 1.8.38
How the Exploit Works
The MyBB application contains a flaw in the Change Avatar function. This function does not properly sanitize user input, thus allowing a remote attacker to craft a malicious request that can obtain sensitive information. This issue could be potentially exploited by attackers to gain unauthorized access to user data or system resources.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited using a crafted HTTP request:
POST /usercp.php?action=do_avatar HTTP/1.1
Host: target.example.com
Content-Type: multipart/form-data;
--boundary
Content-Disposition: form-data; name="my_post_key"
{ "malicious_payload": "..." }
--boundary--This payload could potentially allow an attacker to manipulate the Change Avatar function to retrieve sensitive data or compromise the system.
Mitigation
To mitigate this vulnerability, users are advised to apply the vendor patch as soon as it is available. In the meantime, employing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation against potential attacks exploiting this vulnerability.
