CVE-2022-35931 is a medium-severity vulnerability affecting the Nextcloud Password Policy app, which is used by Nextcloud server administrators to enforce password rules. The issue arises in versions prior to 22.2.10, 23.0.7, and 24.0.3, where the random password generator component may, in very rare cases, produce common passwords that the password validator is designed to block. This inconsistency means that despite password policies intended to prevent weak or common passwords, the system might still generate and accept such passwords. The vulnerability is categorized under CWE-261, which relates to weak encoding for passwords, indicating that the mechanism for generating or encoding passwords does not sufficiently ensure password strength or uniqueness. Although no known exploits have been reported in the wild, the flaw undermines the integrity of password policies by potentially allowing weak passwords to be used, thereby increasing the risk of unauthorized access through password guessing or brute force attacks. The issue is resolved by upgrading Nextcloud to versions 22.2.10, 23.0.7, or 24.0.3, with no known workarounds available. The vulnerability affects multiple major Nextcloud versions, indicating a broad impact across deployments that have not applied the patch. Nextcloud is a widely used open-source file sharing and collaboration platform, often deployed in enterprise and governmental environments, making this vulnerability relevant for organizations relying on Nextcloud for secure data management and collaboration.

For European organizations, the impact of this vulnerability can be significant, especially for those using Nextcloud as a core component of their IT infrastructure for file sharing, collaboration, and data storage. The generation of weak or common passwords despite enforced policies increases the risk of credential compromise, which can lead to unauthorized access to sensitive data, intellectual property theft, and potential lateral movement within networks. This is particularly critical for sectors handling sensitive personal data under GDPR regulations, such as healthcare, finance, and public administration. The vulnerability could undermine trust in the security posture of affected organizations and potentially lead to regulatory penalties if data breaches occur. Additionally, since Nextcloud is often used in private cloud deployments, the exposure of weak passwords could facilitate insider threats or external attackers gaining footholds in otherwise secure environments. Although no active exploits are known, the presence of this vulnerability increases the attack surface and could be targeted by opportunistic attackers or automated tools scanning for weak password implementations.

To mitigate this vulnerability, European organizations should prioritize upgrading their Nextcloud installations to the patched versions 22.2.10, 23.0.7, or 24.0.3 as soon as possible. Since no workarounds exist, patching is the primary defense. Additionally, organizations should audit their current password policies and generated passwords to identify any weak or common passwords that may have been created prior to patching. Implementing multi-factor authentication (MFA) can provide an additional security layer to reduce the risk of compromised credentials leading to unauthorized access. Monitoring authentication logs for unusual login attempts or patterns indicative of brute force attacks is also recommended. Organizations should consider enforcing external password strength checks or integrating with centralized identity providers that enforce stronger password policies. Finally, educating administrators and users about the importance of strong passwords and secure password management practices will help reduce risks associated with weak credentials.