CVE-2025-59136 is a vulnerability classified under CWE-201, which involves the insertion of sensitive information into sent data within the Efí Bank Gerencianet Oficial application, versions up to 3.1.3. This vulnerability allows an attacker to retrieve embedded sensitive data that is improperly included in outbound communications. The issue arises due to insecure handling or inclusion of sensitive information in data transmissions, which can be intercepted or accessed by unauthorized entities. The CVSS 3.1 base score is 5.3, indicating a medium severity level, with an attack vector of network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction needed (UI:N). The scope is unchanged (S:U), and the impact affects confidentiality only (C:L), with no impact on integrity or availability (I:N/A:N). There are no known exploits in the wild, and no patches have been linked yet. The vulnerability was reserved in September 2025 and published at the end of 2025. The lack of authentication or user interaction requirements makes this vulnerability easier to exploit remotely, potentially allowing attackers to access sensitive financial or personal data embedded in communications sent by the application.

For European organizations, especially financial institutions and businesses using Efí Bank's Gerencianet Oficial, this vulnerability poses a risk of sensitive data leakage. Exposure of embedded sensitive information could lead to unauthorized disclosure of customer financial details, transaction data, or personally identifiable information (PII), undermining confidentiality and potentially violating GDPR and other data protection regulations. The impact is primarily on confidentiality, with no direct effect on system integrity or availability. However, the reputational damage and regulatory penalties resulting from data breaches can be significant. Since the vulnerability can be exploited remotely without authentication or user interaction, attackers could leverage this flaw to intercept or extract sensitive data from network communications, increasing the risk of targeted attacks against European financial entities. The absence of known exploits currently reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time.

Organizations should proactively monitor Efí Bank's advisories for patches addressing CVE-2025-59136 and apply them promptly once available. In the interim, conduct thorough audits of data transmission processes within Gerencianet Oficial to identify and minimize the inclusion of sensitive information in outbound data streams. Implement network-level monitoring and data loss prevention (DLP) tools to detect and block unauthorized transmission of sensitive data. Employ encryption for all data in transit to reduce the risk of interception. Restrict network access to the application to trusted sources and consider deploying web application firewalls (WAFs) with custom rules to detect anomalous data patterns. Additionally, review and tighten application configurations and logging to detect suspicious activities. Educate staff on the risks of data leakage and ensure incident response plans are updated to handle potential data exposure incidents related to this vulnerability.