CVE-2025-41685 Overview
CVE-2025-41685 is an information disclosure vulnerability affecting SMA Sunny Portal. A low-privileged authenticated remote attacker can obtain the username of another registered Sunny Portal user by submitting that user's email address to the application. The flaw is categorized under [CWE-359] (Exposure of Private Personal Information to an Unauthorized Actor).
The vulnerability enables user enumeration and correlation of email addresses to portal usernames. This information supports subsequent credential-stuffing, phishing, and account takeover attempts against Sunny Portal accounts used to manage photovoltaic systems.
Critical Impact
Authenticated attackers can enumerate registered users and link email addresses to usernames, weakening downstream authentication controls.
Affected Products
- SMA Sunny Portal (web application)
- Accounts managing SMA photovoltaic inverter and monitoring deployments
- Refer to CERT-VDE Advisory VDE-2025-050 for the authoritative affected-version list
Discovery Timeline
- 2025-08-19 - CVE-2025-41685 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-41685
Vulnerability Analysis
The vulnerability exists in a Sunny Portal function that accepts an email address as input and returns account information tied to that address. Instead of returning a uniform response regardless of whether the email is registered, the application discloses the associated username to any authenticated caller.
The issue is a business logic and information exposure flaw rather than a memory-safety or injection defect. Exploitation requires only low privileges, meaning any registered Sunny Portal user can query the endpoint. No user interaction from the victim is required, and the attack occurs entirely over the network.
The disclosed username is a persistent identifier used for portal authentication. Combined with a known email address, an attacker gains half of the credential pair needed for a login attempt, brute-force campaign, or targeted phishing message referencing the correct portal username.
Root Cause
The root cause is improper access control over personal information tied to user account lookups. The application returns identity data (username) in response to a query that should either require the requester to be the account owner or return a generic response. This aligns with [CWE-359], where the system exposes private information without verifying authorization.
Attack Vector
An authenticated attacker submits target email addresses through the affected Sunny Portal function. For each registered address, the response contains the corresponding username. The attacker iterates over a list of email addresses harvested from OSINT sources, breach dumps, or organizational directories to build an email-to-username mapping for later use.
No code execution occurs. The vulnerability provides intelligence that enables follow-on attacks against the Sunny Portal login interface and against the human owners of the disclosed accounts. See CERT-VDE Advisory VDE-2025-050 for vendor-supplied technical details.
Detection Methods for CVE-2025-41685
Indicators of Compromise
- High-volume or scripted requests to Sunny Portal account lookup endpoints from a single authenticated session
- Sequential or dictionary-style email address parameters submitted by one user account within a short interval
- Authenticated sessions issuing lookup requests for email addresses outside the caller's organization or customer scope
Detection Strategies
- Instrument the Sunny Portal account lookup endpoint with per-user rate metrics and alert on outliers
- Correlate low-privileged account activity that queries many distinct email addresses with subsequent failed logins to the same portal
- Review web server and application logs for repeated 200-OK responses to email-parameter lookups originating from the same session token
Monitoring Recommendations
- Forward Sunny Portal application logs to a centralized SIEM or data lake for retention and correlation
- Baseline normal lookup volumes per account and generate detections when a user exceeds that baseline
- Monitor authentication telemetry for credential-stuffing patterns targeting usernames that were recently queried through the lookup function
How to Mitigate CVE-2025-41685
Immediate Actions Required
- Review CERT-VDE Advisory VDE-2025-050 and apply the vendor-supplied fix or configuration change once available
- Audit Sunny Portal user accounts and disable inactive or unnecessary low-privileged accounts that could be used for enumeration
- Enforce multi-factor authentication on all Sunny Portal accounts to reduce the value of disclosed usernames
Patch Information
SMA and CERT-VDE coordinate remediation guidance for Sunny Portal through CERT-VDE Advisory VDE-2025-050. Consult the advisory for the fixed release, deployment date, and any server-side changes required by portal operators. Because Sunny Portal is a hosted service, the fix is applied by the vendor rather than by end users.
Workarounds
- Restrict Sunny Portal account creation and access to trusted personnel to reduce the pool of low-privileged accounts that can query the endpoint
- Rotate usernames where practical so that disclosed identifiers no longer match current login names
- Educate users about phishing that references legitimate Sunny Portal usernames and email pairings
# No local configuration mitigates this hosted service vulnerability.
# Follow the vendor advisory at https://certvde.com/en/advisories/VDE-2025-050
# and enforce MFA on all Sunny Portal accounts through the portal's account settings.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
