CVE-2026-113371 in Nexus Repository
Summary
by MITRE • 11/04/2026
Sonatype Nexus Repository 3 returns the signing passphrase of an APT or YUM repository, through an internal REST endpoint, to a user account that holds only the read privilege for administering that repository. The account does not need the privilege to edit the repository.
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Analysis
by VulDB Data Team • 11/04/2026
The vulnerability identified in Sonatype Nexus Repository 3 represents a critical failure in access control logic within the application's backend architecture. Specifically, an internal REST endpoint designed for administrative operations incorrectly exposes sensitive cryptographic material associated with APT and YUM repositories. This flaw allows any user account possessing only read privileges on a specific repository to retrieve the signing passphrase required to digitally sign packages distributed through that repository. The severity of this issue is compounded by the fact that authentication alone is sufficient; no additional permissions such as edit or admin rights are necessary for an attacker to exploit this information leak, effectively bypassing the principle of least privilege intended by the system's role-based access control model.
From a technical perspective, the root cause lies in improper authorization checks on internal API endpoints. While public-facing interfaces may correctly enforce strict permission boundaries, internal service-to-service or backend REST calls often assume that any authenticated user has sufficient context to perform operations. In this case, the endpoint responsible for retrieving repository configuration details fails to validate whether the requesting principal holds elevated privileges before returning sensitive data like signing passphrases. This misconfiguration means that the confidentiality of cryptographic keys is compromised simply by querying metadata about a repository one can view but not modify. The exposure occurs through standard HTTP responses, making it easily scriptable and automatable for malicious actors who have gained low-level access to the Nexus instance.
The operational impact of this vulnerability is severe due to the critical role signing passphrases play in package management ecosystems like Debian/Ubuntu (APT) and Fedora/CentOS/RHEL (YUM). These passphrases are used to generate GPG signatures that verify the integrity and authenticity of software packages. If an attacker obtains these credentials, they can forge valid digital signatures for malicious binaries or scripts uploaded to the repository. This enables a supply chain attack where compromised artifacts appear legitimate to downstream consumers who rely on signature verification as their primary trust mechanism. Organizations distributing critical infrastructure components via Nexus could inadvertently distribute malware, trojans, or backdoors that bypass security controls relying on package authenticity checks, leading to widespread compromise of dependent systems across the enterprise network.
This vulnerability aligns with CWE-284 Improper Access Control and CWE-359 Exposure of Private Information Within a Web Application. It also maps directly to MITRE ATT&CK technique T1078 Valid Accounts, as exploitation requires valid credentials, and potentially T1195 Supply Chain Compromise if the forged packages are deployed in production environments. The lack of privilege escalation requirements for accessing sensitive data highlights a systemic gap in how internal APIs handle authorization contexts versus external user interfaces.
Mitigation strategies must focus on immediate remediation of the access control logic within Nexus Repository 3. Administrators should apply vendor-provided patches or updates that address this specific endpoint vulnerability as soon as available, ensuring that signing passphrases are restricted to users with explicit edit or administrative privileges for the respective repository. In parallel, organizations should rotate all exposed APT and YUM signing keys immediately upon confirmation of potential exposure, assuming compromise is likely given the ease of exploitation. Future development practices must enforce strict authorization checks on all internal REST endpoints, ensuring that sensitive cryptographic material is never returned to contexts lacking explicit write or administrative permissions. Additionally, implementing comprehensive audit logging for access to repository configuration data can aid in detecting unauthorized retrieval attempts and improving visibility into potential abuse of these API endpoints.