CVE-2025-7785 is an open redirect vulnerability identified in thinkgem JeeSite versions up to 5.12.0. The vulnerability resides in the Single Sign-On (SSO) functionality, specifically within the sso method of the SsoController.java file. The issue arises from improper validation or sanitization of the 'redirect' parameter, which can be manipulated by an attacker to redirect users to arbitrary external URLs. This type of vulnerability is classified as an open redirect, where an attacker crafts a malicious URL that appears to be from a trusted domain but redirects victims to a malicious site. The vulnerability can be exploited remotely without requiring authentication or privileges, and user interaction is necessary as the victim must click on a crafted link. The disclosed CVSS 4.0 score is 5.3 (medium severity), reflecting the moderate risk posed by this vulnerability. The attack vector is network-based, with low attack complexity and no privileges or user authentication required. The impact on confidentiality is none, integrity is low, and availability is none. The vulnerability does not affect system components beyond the redirect functionality, but it can be leveraged in phishing campaigns or combined with other attacks to facilitate credential theft or malware delivery. A patch has been released (commit 3d06b8d009d0267f0255acc87ea19d29d07cedc3) to address this issue, and it is recommended to apply it promptly. No known exploits are currently observed in the wild, but public disclosure increases the risk of exploitation attempts.

For European organizations using thinkgem JeeSite, this vulnerability could be exploited to conduct phishing attacks by redirecting users to malicious websites that mimic legitimate services. This can lead to credential theft, unauthorized access, or malware infections. Although the vulnerability itself does not directly compromise system confidentiality or availability, it undermines user trust and can serve as an entry point for more severe attacks. Organizations in sectors with high reliance on web-based SSO systems, such as government, finance, healthcare, and education, may face increased risks. The open redirect can also facilitate social engineering attacks targeting employees or customers, potentially leading to data breaches or financial fraud. Given the remote exploitability and lack of required privileges, attackers can easily craft malicious URLs and distribute them via email or social media, increasing the threat surface. The medium severity rating suggests that while the vulnerability is not critical, it should not be ignored, especially in environments where JeeSite is integrated into critical workflows or handles sensitive data.

1. Apply the official patch (commit 3d06b8d009d0267f0255acc87ea19d29d07cedc3) provided by thinkgem immediately to fix the open redirect vulnerability. 2. Implement strict validation and sanitization of the 'redirect' parameter to allow only whitelisted internal URLs or domains. 3. Employ Content Security Policy (CSP) headers to restrict navigation and framing to trusted domains. 4. Educate users and employees about the risks of clicking on suspicious links, especially those appearing to come from trusted sources. 5. Monitor web server logs for unusual redirect patterns or spikes in traffic to external URLs. 6. Use web application firewalls (WAF) to detect and block malicious redirect attempts. 7. Review and harden SSO configurations to minimize exposure to redirect-based attacks. 8. Conduct regular security assessments and penetration testing focusing on authentication and redirect mechanisms.