CVE-2025-41685 is a vulnerability identified in SMA's ennexos.sunnyportal.com platform, which is a web-based portal likely used for monitoring and managing solar energy systems. The vulnerability is classified under CWE-359, which pertains to the Exposure of Private Personal Information to an Unauthorized Actor. Specifically, this vulnerability allows a low-privileged remote attacker to obtain the username of another registered Sunny Portal user by simply submitting that user's email address. This indicates an information disclosure flaw where the system responds differently or reveals identifiable information when queried with an email address, enabling attackers to enumerate valid usernames. The CVSS 3.1 base score is 6.5, categorized as medium severity, with the vector AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N. This means the attack can be performed remotely over the network with low attack complexity, requires low privileges (authenticated user), no user interaction, and impacts confidentiality with high impact, but does not affect integrity or availability. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability could be leveraged as a reconnaissance step in a broader attack chain, such as targeted phishing, credential stuffing, or further exploitation attempts, by confirming valid usernames associated with email addresses. The affected version is listed as '0', which may indicate all versions or a placeholder, so it is important for users of the Sunny Portal platform to verify their exposure status and await vendor advisories.

For European organizations using SMA's Sunny Portal platform, this vulnerability poses a risk primarily to user privacy and confidentiality. Exposure of usernames linked to email addresses can facilitate targeted social engineering attacks, spear phishing, or brute force attempts, potentially leading to unauthorized access to sensitive energy management systems. Given that Sunny Portal is used to monitor solar installations, unauthorized access could indirectly affect operational security and energy management. While the vulnerability itself does not allow direct system compromise or data manipulation, it lowers the barrier for attackers to identify valid user accounts, increasing the likelihood of subsequent attacks. In Europe, where data privacy regulations such as GDPR impose strict requirements on personal data protection, this exposure could lead to compliance issues and reputational damage if exploited. Organizations relying on this platform for critical infrastructure monitoring should consider the potential cascading effects of compromised user accounts, especially in sectors like energy utilities, manufacturing, and smart building management.

To mitigate this vulnerability, European organizations should first verify if their Sunny Portal instances are affected by checking with SMA for official advisories or patches. Until a patch is available, organizations should implement strict access controls and monitor authentication logs for unusual activity indicative of username enumeration attempts. Rate limiting or CAPTCHA mechanisms on email-to-username lookup functionalities can reduce automated enumeration risks. Additionally, enforcing strong multi-factor authentication (MFA) for all users will mitigate the risk of account compromise even if usernames are exposed. User awareness training should emphasize the risks of phishing and social engineering attacks that could leverage exposed usernames. Network-level protections such as web application firewalls (WAFs) can be configured to detect and block suspicious requests targeting user enumeration endpoints. Finally, organizations should conduct regular security assessments and penetration tests focusing on information disclosure vectors to proactively identify and remediate similar issues.