CVE-2025-61136 is a vulnerability identified in axewater sharewarez version 2.4.3, specifically within its password reset functionality. The root cause is a Host Header Injection flaw that occurs because the application uses Flask's url_for function with the _external=True parameter to generate password reset URLs without a fixed SERVER_NAME configuration. Flask's url_for(_external=True) relies on the Host header to construct absolute URLs. When SERVER_NAME is not set, an attacker can manipulate the Host header in HTTP requests to inject arbitrary domain names into the generated password reset links. This allows an attacker to craft password reset emails containing links that redirect victims to attacker-controlled domains. Consequently, attackers can perform password reset poisoning, tricking users into resetting their passwords on malicious sites, which can lead to account takeover. The vulnerability does not require authentication or user interaction beyond clicking the malicious link. Although no exploits are currently known in the wild, the flaw presents a significant risk due to the sensitive nature of password reset processes. The absence of a CVSS score suggests this is a newly published vulnerability (October 2025) and requires immediate attention. The vulnerability is particularly critical in environments where axewater sharewarez is used for user management and authentication. The lack of a patch link indicates that remediation may require configuration changes or custom code fixes. The vulnerability highlights the importance of proper Host header validation and secure URL generation in web applications, especially those built on Flask frameworks.

For European organizations, this vulnerability poses a high risk to user account security and overall trust in affected applications. Successful exploitation can lead to unauthorized account access, enabling attackers to impersonate legitimate users, access sensitive data, or perform fraudulent activities. Organizations in sectors such as finance, healthcare, and government, where user identity integrity is critical, could face severe reputational damage and regulatory penalties under GDPR if account takeovers lead to data breaches. The attack vector requires no authentication and can be executed remotely, increasing the attack surface. Additionally, phishing campaigns leveraging poisoned password reset links could amplify the impact by deceiving users into divulging credentials or other sensitive information. The lack of known exploits in the wild provides a window for proactive mitigation, but the potential for rapid weaponization remains. European entities relying on axewater sharewarez for authentication or password management must prioritize addressing this vulnerability to prevent compromise and maintain compliance with data protection regulations.

To mitigate CVE-2025-61136, organizations should first configure the Flask application to set a fixed SERVER_NAME value. This ensures that url_for(_external=True) generates URLs with a trusted domain, preventing Host header manipulation. If setting SERVER_NAME is not feasible, implement strict validation of incoming Host headers against a whitelist of allowed domains before processing password reset requests. Additionally, consider overriding or customizing the password reset URL generation logic to use static or validated domains rather than relying on the Host header. Employ web application firewalls (WAFs) to detect and block suspicious Host header values indicative of injection attempts. Educate users to verify password reset email URLs and report suspicious links. Regularly audit and update the axewater sharewarez software and monitor vendor communications for official patches or updates. Finally, implement multi-factor authentication (MFA) to reduce the impact of compromised credentials resulting from account takeover attempts.