CVE-2025-69602 identifies a session fixation vulnerability in the 66biolinks v62.0.0 application developed by AltumCode. The core issue lies in the application's failure to regenerate the session identifier (session ID) after a user successfully authenticates. Normally, regenerating the session ID upon login is a critical security measure to prevent session fixation attacks, where an attacker sets or predicts a session ID and tricks a user into authenticating with that session. Because 66biolinks reuses the same session cookie value for users logging in from the same browser, an attacker who can set or guess the session ID beforehand can hijack the authenticated session, gaining unauthorized access to the victim’s account and potentially sensitive information. The vulnerability is classified under CWE-384 (Session Fixation). The CVSS v3.1 base score is 9.1 (critical), reflecting network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality and integrity. Although no public exploits are currently known, the vulnerability poses a significant risk due to its ease of exploitation and the sensitive nature of session management in web applications. The lack of session ID regeneration after login is a fundamental security flaw that undermines the trustworthiness of user sessions in 66biolinks.

For European organizations using 66biolinks, this vulnerability can lead to severe consequences including unauthorized access to user accounts, data breaches, and potential compromise of sensitive business or customer information. Attackers exploiting this flaw can impersonate legitimate users without needing credentials, leading to data theft, fraud, or further lateral movement within the network. Given the critical CVSS score, the confidentiality and integrity of affected systems are at high risk. The availability impact is low, but the breach of trust and potential regulatory consequences under GDPR for data exposure could be substantial. Organizations in sectors such as finance, healthcare, and e-commerce, where 66biolinks might be used for link management or marketing, are particularly vulnerable. The risk is amplified in environments where session cookies are not secured with additional protections like HttpOnly or Secure flags. The absence of known exploits in the wild provides a window for proactive mitigation, but the critical nature demands urgent attention.

Immediate mitigation involves updating 66biolinks to a version where the session fixation vulnerability is patched; however, no patch links are currently provided, so organizations should monitor for official updates from AltumCode. In the interim, organizations should implement server-side session management best practices, including enforcing session ID regeneration immediately after successful authentication to invalidate any attacker-set session IDs. Additionally, configure session cookies with the Secure and HttpOnly flags to reduce the risk of interception and cross-site scripting attacks. Employ web application firewalls (WAFs) to detect and block suspicious session-related activities. Conduct thorough security audits of session management logic and educate developers on secure session handling. Monitoring for unusual session activity and implementing multi-factor authentication can further reduce the risk of session hijacking. Finally, organizations should prepare incident response plans to quickly address any exploitation attempts.