CVE-2026-14645 in Nexus Repository
Summary
by MITRE • 07/14/2026
Nexus Repository 3 does not validate the destination of the "Webhook: Global" capability's configured URL before making an outbound HTTP request, allowing a user holding the Capability Administration permission to cause the server to send requests to internal network locations (Server-Side Request Forgery). This permission is granted by role assignment, independent of authentication status, so an unauthenticated user could also trigger this behavior if the anonymous role has been granted the permission.
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Analysis
by VulDB Data Team • 07/14/2026
The vulnerability in Nexus Repository 3 stems from inadequate input validation within the Webhook: Global capability functionality, creating a server-side request forgery (ssrf) attack vector that can be exploited by users with specific permission levels. This flaw exists because the system fails to validate or sanitize the destination URL before initiating outbound HTTP requests, allowing malicious actors to manipulate where webhook notifications are sent. The vulnerability specifically affects the global webhook configuration feature that enables administrators to set up automated notifications when repository events occur, such as artifact uploads or deletions.
The technical implementation of this flaw allows an attacker with the Capability Administration permission to specify arbitrary URLs for webhook destinations without proper validation. This permission model operates independently of authentication status, meaning that even unauthenticated users could potentially trigger the vulnerability if the anonymous role has been granted the capability administration rights. The system's trust in user-provided URLs extends to internal network resources, creating a pathway for attackers to probe internal systems, access sensitive information, or redirect traffic to malicious endpoints.
The operational impact of this vulnerability is significant as it enables attackers to perform reconnaissance on internal network infrastructure that would otherwise be protected by firewalls and network segmentation. Attackers can leverage this vulnerability to map internal services, test for vulnerabilities in internal systems, or even redirect webhook notifications to external servers they control. The risk escalates when considering that the anonymous role assignment model means unauthenticated access could potentially trigger these requests, expanding the attack surface beyond authenticated users. This particular weakness allows for lateral movement within networks and can serve as a stepping stone for more extensive attacks.
The vulnerability aligns with CWE-918, which specifically addresses server-side request forgery vulnerabilities where applications fail to properly validate or sanitize user-supplied URLs before making outbound requests. From an attack perspective, this flaw maps to multiple ATT&CK techniques including T1071.004 for application layer protocol: DNS and T1566 for credential access through social engineering. Organizations should implement strict URL validation mechanisms that ensure webhook destinations are properly sanitized and validated against known safe domains or IP ranges. The recommended mitigations include implementing network-level restrictions, enforcing outbound traffic controls, and ensuring that the anonymous role is carefully configured to prevent unauthorized capability administration permissions. Regular security audits of role assignments and permission models should be conducted to prevent unintended access to critical administrative functions.
The exploitation potential increases when considering that webhook functionality often carries sensitive information about repository activities, including artifact metadata, user actions, and potentially even authentication tokens or credentials stored within the repository system. This vulnerability essentially allows attackers to intercept or manipulate these notifications, potentially leading to privilege escalation or data exfiltration attacks. Organizations should also consider implementing network segmentation strategies that limit outbound connectivity from repository servers and establish strict policies around URL validation for all webhook configurations. The root cause demonstrates a fundamental security principle violation where user input is trusted without proper sanitization, highlighting the importance of defense-in-depth approaches in securing enterprise software systems.