CVE-2025-4515 is a medium-severity vulnerability affecting Zylon PrivateGPT versions up to 0.6.2. The issue arises from a permissive cross-domain policy configured via the allow_origins argument in the settings.yaml file. This misconfiguration allows untrusted domains to bypass the same-origin policy, potentially enabling malicious websites to interact with the PrivateGPT application remotely. The vulnerability does not require authentication or privileges and can be exploited over the network without user interaction, although some user interaction is indicated by the CVSS vector (UI:P). The flaw could lead to limited integrity impacts, such as unauthorized actions or data manipulation within the context of the affected application, and some confidentiality impact due to cross-origin data exposure. The vendor was notified but has not responded or issued a patch, and while no known exploits are currently in the wild, public disclosure increases the risk of exploitation. The CVSS 4.0 score of 5.3 reflects a medium risk, with network attack vector, low attack complexity, no privileges required, and partial integrity impact. The vulnerability specifically targets the cross-origin resource sharing (CORS) or cross-domain policy configuration, a common web security control that, if misconfigured, can lead to cross-site request forgery (CSRF), cross-site scripting (XSS), or data theft attacks. Since Zylon PrivateGPT is a product used for private AI model interactions, unauthorized cross-origin access could expose sensitive AI query data or allow manipulation of the AI interface, undermining confidentiality and integrity of user data and operations.

For European organizations using Zylon PrivateGPT, this vulnerability could lead to unauthorized access or manipulation of sensitive AI-driven data and services. Organizations relying on PrivateGPT for confidential or proprietary information processing may face data leakage or integrity compromise if attackers exploit the permissive cross-domain policy. This could impact sectors with high data sensitivity such as finance, healthcare, legal, and government agencies. The remote exploitability and lack of required privileges increase the risk of widespread exploitation, especially in environments where PrivateGPT is exposed to the internet or integrated into web portals. The absence of vendor response and patches means organizations must proactively mitigate the risk. Exploitation could result in reputational damage, regulatory non-compliance (e.g., GDPR breaches due to data exposure), and operational disruption if attackers manipulate AI responses or extract confidential information. However, the medium severity and partial integrity impact suggest the threat is serious but not critical, with no direct availability impact reported.

European organizations should immediately audit their PrivateGPT deployments to identify if versions 0.6.0 through 0.6.2 are in use. Since no official patch is available, mitigation should focus on configuration hardening: specifically, restrict the allow_origins setting in settings.yaml to only trusted domains, avoiding wildcards or broad domain patterns. Implement strict Content Security Policy (CSP) headers and validate all cross-origin requests server-side. Network-level controls such as web application firewalls (WAFs) can be configured to block suspicious cross-origin requests. Organizations should also isolate PrivateGPT instances behind VPNs or internal networks where possible, limiting exposure to the public internet. Monitoring and logging cross-origin requests can help detect exploitation attempts. Additionally, organizations should engage with Zylon for updates and consider alternative AI solutions if timely patches are not forthcoming. Employee awareness about phishing or social engineering that could trigger cross-origin attacks is also recommended.