CVE-2025-11843 is an authentication bypass vulnerability classified under CWE-290, discovered in Therefore Corporation GmbH's Therefore Online and Therefore On-Premises document management solutions. The flaw allows a remote attacker to impersonate either the web service account or an API service account when connecting to the Therefore Server without any authentication, due to insufficient verification mechanisms in the authentication process. This impersonation occurs at the application level, meaning the attacker can gain access to the Therefore system's document repositories and potentially exfiltrate sensitive information stored therein. The vulnerability does not extend to operating system-level access, limiting the scope to the application environment. The CVSS 4.0 vector indicates the attack can be performed remotely (AV:N), with low attack complexity (AC:L), no authentication required (AT:N), and no user interaction (UI:N). The impact on confidentiality is high (VC:H), with low impact on integrity (VI:L), and no impact on availability (VA:N). The vulnerability is currently unpatched, and no known exploits have been observed in the wild, but the high severity score (8.8) demands urgent attention. The vulnerability was reserved and published in October 2025, highlighting its recent discovery. Given the critical nature of document management systems in enterprise environments, exploitation could lead to unauthorized disclosure of sensitive corporate or personal data.

For European organizations, the impact of CVE-2025-11843 is significant due to the potential unauthorized access to confidential documents stored within Therefore systems. This could result in data breaches involving intellectual property, personal data protected under GDPR, and other sensitive corporate information. The breach of confidentiality could lead to regulatory penalties, reputational damage, and financial losses. Since Therefore is used in various sectors including legal, finance, and government, the compromise of document integrity and confidentiality could disrupt business operations and erode trust. The lack of required authentication and ease of exploitation increase the risk of widespread attacks, especially in organizations with exposed or poorly segmented network environments. Additionally, the absence of operating system-level compromise limits lateral movement but does not diminish the severity of data exposure within the application context. European organizations must consider the regulatory implications of data breaches and the potential for targeted attacks leveraging this vulnerability.

To mitigate CVE-2025-11843, European organizations should implement the following specific measures: 1) Immediately restrict network access to Therefore Online and On-Premises servers by implementing strict firewall rules and network segmentation, limiting API and web service access to trusted hosts only. 2) Monitor and audit API and web service account activities for unusual or unauthorized access patterns using SIEM tools to detect potential exploitation attempts early. 3) Apply any vendor-provided patches or updates as soon as they become available; maintain close communication with Therefore Corporation for security advisories. 4) Enforce strong authentication and authorization controls around the Therefore environment, including multi-factor authentication for administrative access and service accounts where possible. 5) Conduct regular security assessments and penetration testing focused on authentication mechanisms within Therefore deployments. 6) Implement data encryption at rest and in transit to reduce the impact of unauthorized access. 7) Educate IT and security teams about this vulnerability and ensure incident response plans include scenarios involving application-level impersonation attacks. These targeted actions go beyond generic advice by focusing on network-level controls, monitoring, and vendor coordination specific to Therefore products.