CVE-2023-4895 is a medium-severity vulnerability affecting GitLab Enterprise Edition (EE) versions from 12.0 up to 16.7.6, as well as versions 16.8 before 16.8.3 and 16.9 before 16.9.1. The vulnerability is classified under CWE-862, which corresponds to Missing Authorization. Specifically, this flaw allows an attacker with limited privileges (requiring some level of authentication) to bypass the 'group IP restriction' settings configured in GitLab. These IP restrictions are intended to limit access to environment details of projects to certain IP ranges. However, due to this vulnerability, an authenticated user with low privileges can circumvent these restrictions and gain unauthorized access to sensitive environment details associated with projects. Environment details in GitLab often include environment variables, deployment configurations, and other metadata that could contain sensitive information such as API keys, credentials, or infrastructure details. The vulnerability does not require user interaction beyond authentication, and the attack vector is network-based (remote). The CVSS 3.1 base score is 4.3, indicating a medium severity primarily due to the limited confidentiality impact and the requirement for some privileges (PR:L). There is no known exploitation in the wild as of the published date, and no official patches are linked in the provided data, though it is expected that GitLab has or will release fixes given the disclosure. This vulnerability impacts the confidentiality of environment details but does not affect integrity or availability. The scope is unchanged, meaning the vulnerability affects only the vulnerable component (GitLab EE).

For European organizations using GitLab EE, this vulnerability poses a risk of unauthorized disclosure of sensitive environment details within projects. Such information leakage could enable further attacks, including credential theft, lateral movement, or supply chain compromises if environment variables contain secrets or deployment configurations. Organizations relying on IP-based restrictions to secure access to critical deployment environments may have a false sense of security, as this vulnerability allows bypassing those controls. This is particularly concerning for enterprises with strict compliance requirements (e.g., GDPR) where unauthorized access to sensitive data can lead to regulatory penalties and reputational damage. The impact is more pronounced in organizations with large, complex GitLab deployments managing critical infrastructure or production environments. However, since exploitation requires at least some level of authenticated access, the risk is somewhat mitigated by existing access controls. Still, insider threats or compromised low-privilege accounts could exploit this flaw to escalate information access. Overall, the vulnerability could facilitate reconnaissance and information gathering that precedes more severe attacks.

1. Upgrade GitLab EE to the latest patched versions beyond 16.7.6, 16.8.3, and 16.9.1 as soon as official patches are available from GitLab. 2. In the interim, restrict user privileges rigorously, ensuring that only trusted users have access to projects with sensitive environment details. 3. Review and tighten authentication and authorization policies, including multi-factor authentication (MFA) to reduce risk of account compromise. 4. Audit existing environment variables and project configurations to remove or rotate any sensitive secrets that could be exposed. 5. Consider additional network-level controls such as VPNs or zero-trust segmentation to limit access to GitLab instances beyond IP restrictions. 6. Monitor GitLab logs for unusual access patterns or attempts to access environment details by users without appropriate privileges. 7. Educate development and DevOps teams about the risk and encourage prompt reporting of suspicious activity. 8. If possible, temporarily disable or limit the use of 'group IP restriction' settings until patches are applied, or implement compensating controls to enforce environment access restrictions.