CVE-2026-25811 is an authorization vulnerability classified under CWE-863 affecting PlaciPy version 1.0.0, a placement management system developed by Praskla-Technology for educational institutions. The core issue arises from the application's method of tenant identification: it derives the tenant ID directly from the email domain provided by users during login or registration without verifying if the user legitimately owns or controls that domain. This flawed logic allows an attacker to impersonate or claim a tenant identity simply by using an email address with a domain matching another tenant. Consequently, the attacker can gain unauthorized access to data belonging to other tenants, violating confidentiality boundaries. The vulnerability is remotely exploitable over the network without requiring user interaction and only requires low privileges, making it relatively easy to exploit. The CVSS 4.0 score of 5.3 reflects a medium severity, primarily due to the limited scope of impact (tenant data leakage) and the absence of integrity or availability compromise. No patches or fixes are currently published, and no known exploits have been reported in the wild. The vulnerability highlights a critical design flaw in multi-tenant SaaS applications where tenant isolation depends on unverified user input. Proper domain ownership validation, such as DNS verification or email confirmation workflows, is necessary to prevent unauthorized cross-tenant access.

The primary impact of CVE-2026-25811 is unauthorized disclosure of sensitive data across tenants in the PlaciPy system. For European educational institutions, this could mean exposure of student placement records, personal information, and institutional data to unauthorized parties, potentially violating GDPR and other data protection regulations. The breach of confidentiality can undermine trust in the affected institutions and lead to legal and reputational consequences. Since the vulnerability allows cross-tenant data access without authentication, attackers could systematically harvest data from multiple tenants if they can register or authenticate with manipulated email domains. Although the vulnerability does not affect data integrity or system availability, the confidentiality breach alone is significant given the sensitivity of educational data. The lack of current exploits reduces immediate risk, but the ease of exploitation and the critical nature of the data involved make this a serious concern for European organizations using PlaciPy 1.0.0. Additionally, regulatory scrutiny in Europe may increase the impact due to strict data protection laws.

1. Implement robust domain ownership verification mechanisms before assigning tenant identifiers based on email domains. This can include DNS TXT record verification, email-based domain confirmation workflows, or integration with domain registrars. 2. Enforce strict tenant isolation at the application layer, ensuring that access controls do not rely solely on user-provided email domains. 3. Apply the principle of least privilege by restricting user permissions and monitoring access patterns for anomalies indicative of cross-tenant access attempts. 4. Conduct thorough code reviews and security testing focused on multi-tenancy and authorization logic. 5. Until an official patch is released by Praskla-Technology, consider deploying compensating controls such as network segmentation, enhanced logging, and alerting on suspicious tenant access. 6. Educate administrators and users about the risk and encourage reporting of suspicious activity. 7. Regularly audit tenant data access logs to detect unauthorized cross-tenant data access. 8. Engage with the vendor for timely updates and patches, and plan for prompt deployment once available.