CVE-2026-54865 in Podamibe Custom User Gravatar Plugin
Summary
by MITRE • 10/29/2026
Subscriber Cross Site Scripting (XSS) in Podamibe Custom User Gravatar <= 1.0.8 versions.
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Analysis
by VulDB Data Team • 10/29/2026
The vulnerability identified as a Subscriber-level Cross-Site Scripting issue within the Podamibe Custom User Gravatar plugin, specifically affecting versions up to and including 1.0.8, represents a significant security risk for WordPress installations that utilize this functionality. This flaw stems from insufficient input validation and output encoding mechanisms when handling user-provided data related to gravatar profiles or custom avatar settings. In the context of web application security, Cross-Site Scripting occurs when an attacker can inject malicious scripts into pages viewed by other users. Because this vulnerability is accessible to subscribers, it indicates a failure in privilege separation logic, allowing lower-privileged accounts to execute code that typically requires higher administrative privileges or affects all visitors regardless of their role.
From a technical perspective, the root cause lies in how the plugin processes and renders user input associated with avatar configurations. When a subscriber submits data for their custom gravatar settings, such as alternative image URLs or profile metadata, the application fails to properly sanitize these inputs before storing them or rendering them back into HTML contexts without adequate encoding. This allows an attacker to craft a payload containing JavaScript code that is embedded within the user's profile information. Upon subsequent page loads where this data is displayed, typically on public-facing pages like author archives, comment sections, or user profiles, the browser interprets and executes the injected script as part of the legitimate webpage content.
The operational impact of this vulnerability extends beyond simple defacement or annoyance. Since Cross-Site Scripting attacks can be leveraged for session hijacking, attackers can steal authentication cookies from other users who view the compromised page. This could lead to unauthorized access to user accounts if those sessions are active and not properly secured with HttpOnly flags or secure cookie attributes. Furthermore, in environments where subscribers have limited but non-trivial permissions, such as contributing content or managing specific site features, an XSS attack can be used to perform actions on behalf of the victim without their knowledge. This includes changing account settings, posting malicious links, or even escalating privileges if combined with other vulnerabilities like Cross-Site Request Forgery weaknesses in administrative endpoints that might trust cookies from compromised sessions.
This vulnerability aligns closely with CWE-79, which defines Improper Neutralization of Input During Web Page Generation commonly known as Cross-site Scripting. It also maps to the MITRE ATT&CK framework under techniques such as Client-side Injection (T1059) and potentially Credential Access via Browser Session Hijacking if cookies are stolen. The presence of this flaw suggests that the plugin developer did not implement robust security controls consistent with OWASP guidelines for preventing XSS, particularly regarding context-aware output encoding and strict input validation based on expected data types rather than relying solely on blacklist approaches which can be easily bypassed using obfuscation techniques or alternative event handlers in JavaScript.
Mitigation strategies should focus primarily on immediate remediation through software updates. Administrators running Podamibe Custom User Gravatar versions 1.0.8 and below are strongly advised to upgrade to the latest patched version where this issue has been resolved by implementing proper sanitization functions like wp_kses_post or esc_attr depending on the context, ensuring that all special characters in user input are encoded before being outputted to the browser. If an update is not immediately available, temporary mitigations include restricting subscriber capabilities via role management plugins to prevent them from accessing the specific avatar configuration endpoints until a patch is released. Additionally, implementing Content Security Policy headers can help mitigate the impact of successful XSS attacks by restricting the sources from which scripts are allowed to execute, thereby preventing the injection and execution of arbitrary code even if it manages to bypass input validation checks. Regular security audits and penetration testing should be conducted on all third-party plugins to ensure they adhere to current web application security standards and do not introduce similar vulnerabilities into the broader ecosystem.