CVE-2023-3384 is a vulnerability in Red Hat Quay 3, a widely used container image registry solution. The vulnerability is a Cross-site Scripting (XSS) flaw caused by improper neutralization of input during web page generation. Specifically, while image labels created through the Quay UI and backend undergo validation via a regex pattern in validation.py, this validation is not applied to labels that originate from container images themselves. This discrepancy allows an attacker to craft and publish a malicious container image to a public registry with a label containing executable script code. When a user views the image labels in the Quay web interface, the malicious script can execute in their browser context. The CVSS 3.1 score is 5.4 (medium), reflecting that the attack vector is network-based, requires low complexity, privileges (push rights) are needed, and user interaction is required to trigger the XSS. The scope is changed, meaning the vulnerability affects components beyond the initially vulnerable component. The impact includes limited confidentiality and integrity loss, such as session token theft or UI manipulation, but no direct availability impact. No public exploits have been reported yet. This vulnerability highlights the importance of consistent input validation across all data sources, especially in container registries that serve as critical infrastructure in DevOps pipelines.

For European organizations, this vulnerability could lead to unauthorized script execution within the context of the Red Hat Quay 3 web interface. Potential impacts include theft of user session tokens, unauthorized actions performed on behalf of users, and manipulation of the registry UI to mislead users or inject further malicious content. Since container registries are integral to software supply chains, exploitation could undermine trust in container images and disrupt development and deployment workflows. Organizations relying on public or shared registries are at higher risk, especially if they allow users to push images without strict controls. The confidentiality and integrity of container metadata and user sessions are at risk, which could cascade into broader security issues if attackers leverage stolen credentials or session tokens to escalate privileges or access other systems. However, the requirement for push privileges and user interaction limits the ease of exploitation. The absence of known exploits in the wild reduces immediate risk but does not eliminate it, so proactive mitigation is essential.

European organizations should implement the following specific mitigations: 1) Upgrade Red Hat Quay 3 to the latest patched version as soon as it becomes available from Red Hat, ensuring that the image label validation is consistently applied. 2) Restrict push permissions to trusted users only and enforce strong authentication and authorization controls to limit who can upload images. 3) Implement web application firewall (WAF) rules to detect and block suspicious script payloads in image labels or related HTTP requests. 4) Monitor registry logs for unusual image uploads or label content that may indicate exploitation attempts. 5) Educate users to avoid clicking on suspicious links or interacting with untrusted images in the registry UI. 6) Consider isolating the registry interface behind VPN or internal networks to reduce exposure. 7) Employ Content Security Policy (CSP) headers in the Quay web interface to mitigate the impact of potential XSS by restricting script execution contexts. 8) Conduct regular security audits and penetration testing focused on the container registry environment to identify similar input validation issues.