CVE-2025-67999 identifies a Blind SQL Injection vulnerability in Stefano Lissa's Newsletter software, affecting all versions up to and including 9.0.9. The vulnerability arises from improper neutralization of special elements in SQL commands, allowing an attacker to inject malicious SQL queries that the backend database executes. Blind SQL Injection means the attacker cannot directly see the query results but can infer data through response behavior or timing, enabling extraction of sensitive information such as user credentials, subscriber lists, or internal configuration data. The CVSS vector indicates network attack vector (AV:N), low attack complexity (AC:L), but requires high privileges (PR:H) and no user interaction (UI:N). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The impact is high on confidentiality (C:H), low on integrity (I:L), and none on availability (A:N). No patches are currently linked, and no known exploits have been reported, but the vulnerability is publicly disclosed and should be considered exploitable. The vulnerability could be exploited by authenticated users with elevated privileges, such as newsletter administrators or editors, to extract or manipulate database content. This flaw poses a significant risk to organizations relying on this software for managing newsletter subscriptions and communications.

For European organizations, exploitation of this vulnerability could lead to unauthorized disclosure of subscriber data, internal communications, and potentially sensitive business information stored within the newsletter system's database. This breach of confidentiality can result in reputational damage, regulatory penalties under GDPR, and loss of customer trust. Partial integrity loss could allow attackers to manipulate newsletter content or subscriber data, potentially facilitating phishing campaigns or misinformation. The lack of availability impact means services remain operational, but the data compromise risk remains high. Organizations in sectors such as media, marketing, and public relations that rely heavily on newsletter tools are particularly vulnerable. The requirement for high privileges limits exploitation to insiders or compromised accounts, but insider threats or credential theft scenarios increase risk. The absence of known exploits in the wild currently reduces immediate threat but does not eliminate future risk, especially as the vulnerability is publicly known.

European organizations should immediately audit their use of Stefano Lissa Newsletter software and identify affected versions (up to 9.0.9). Until a vendor patch is released, restrict access to the newsletter management interface to trusted administrators only and enforce strong authentication mechanisms, including multi-factor authentication. Implement strict input validation and sanitization on all user inputs related to SQL queries, even if the software does not currently do so. Monitor database query logs for anomalous or suspicious patterns indicative of SQL injection attempts. Employ web application firewalls (WAFs) with custom rules to detect and block SQL injection payloads targeting the newsletter application. Regularly review user privileges and remove unnecessary high-level access to minimize the attack surface. Once a patch is available, prioritize prompt deployment and verify the fix through security testing. Additionally, conduct security awareness training for administrators to recognize potential exploitation signs and maintain incident response readiness.