CVE-2025-51863 is a Self Cross Site Scripting (XSS) vulnerability identified in the ChatGPT Unli platform (ChatGPTUnli.com), disclosed in July 2025. This vulnerability allows an attacker to execute arbitrary code by submitting a specially crafted SVG (Scalable Vector Graphics) file to the chat interface. The vulnerability is classified as a Self XSS, meaning the malicious payload is executed in the context of the user's own browser session when they interact with the crafted SVG content. SVG files can contain embedded scripts, and if the chat interface does not properly sanitize or validate SVG inputs, it can lead to script execution. Although the affected versions are not specified, the vulnerability is present up to May 26, 2025. No official patches or fixes have been linked yet, and there are no known exploits in the wild at the time of publication. The absence of a CVSS score indicates that the vulnerability has not been formally scored for severity, but the nature of the attack vector suggests a client-side code execution risk. The attack requires user interaction, specifically the user loading or interacting with the malicious SVG content within the chat interface. Since this is a Self XSS, the attacker typically needs to convince the victim to perform the action themselves, often through social engineering or phishing. The vulnerability impacts the confidentiality and integrity of the user's session and potentially the broader application if session tokens or sensitive data are exposed or manipulated. Availability impact is limited but could be leveraged for further attacks. The lack of authentication requirements for the attack vector is unclear but likely depends on the chat interface's access controls. Overall, this vulnerability highlights the risks of insufficient input sanitization in web-based chat platforms that accept rich media content such as SVG files.

For European organizations using ChatGPT Unli or similar chat platforms that accept SVG inputs, this vulnerability poses a risk primarily to end users who interact with the chat interface. Successful exploitation could lead to execution of arbitrary scripts in the user's browser, enabling theft of session cookies, user credentials, or other sensitive information. This could facilitate account takeover or unauthorized access to organizational resources. Additionally, attackers could use the vulnerability to deliver further malware or conduct phishing attacks within the trusted chat environment. The impact is particularly significant for organizations relying on ChatGPT Unli for internal communications or customer interactions, as compromised user sessions could lead to data leakage or reputational damage. Since the vulnerability requires user interaction, the risk can be mitigated by user awareness, but the potential for social engineering remains high. The absence of known exploits reduces immediate risk, but the public disclosure increases the likelihood of future exploitation attempts. European organizations with strict data protection regulations (e.g., GDPR) must consider the potential compliance implications if user data is compromised through this vulnerability.

1. Immediate mitigation should focus on disabling or restricting SVG file uploads or rendering within the chat interface until a proper fix is available. 2. Implement robust input validation and sanitization on all user-supplied content, especially SVG files, to strip or neutralize embedded scripts and potentially dangerous elements. 3. Employ Content Security Policy (CSP) headers to restrict script execution sources and reduce the impact of XSS attacks. 4. Educate users about the risks of interacting with untrusted or unexpected content in chat platforms, emphasizing caution with file uploads or links. 5. Monitor chat logs and user activity for suspicious behavior indicative of exploitation attempts. 6. Coordinate with ChatGPT Unli developers or vendors to obtain patches or updates addressing this vulnerability promptly. 7. Consider implementing multi-factor authentication (MFA) to reduce the impact of compromised credentials resulting from XSS attacks. 8. Conduct regular security assessments and penetration testing focused on input handling and client-side vulnerabilities in chat applications.