CVE-2026-113372 in Nexus Repository
Summary
by MITRE • 11/04/2026
Sonatype Nexus Repository 3 returns the private signing key of a YUM proxy or group repository to an account that holds only the read privilege for administering that repository. The account does not need the privilege to edit the repository. A party that holds the key can sign repository metadata as that repository.
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Analysis
by VulDB Data Team • 11/04/2026
Sonatype Nexus Repository 3 contains a critical information disclosure vulnerability affecting YUM proxy and group repositories, where private signing keys are inadvertently exposed to users with only read privileges for administration purposes. This flaw represents a significant deviation from the principle of least privilege, allowing individuals who should have no ability to modify repository configurations or content to access sensitive cryptographic material intended solely for secure operations by authorized administrators. The vulnerability stems from an improper authorization check within the API endpoints responsible for retrieving repository configuration details, specifically those related to YUM metadata signing settings.
The technical root cause lies in the application's failure to validate whether a user requesting private key data possesses the necessary administrative write permissions rather than just read access. In standard security architectures, private keys used for code or package signing must be treated as highly sensitive secrets, accessible only by processes and users with explicit permission to perform cryptographic operations. By exposing these keys through endpoints that are otherwise restricted to read-only administrators, the system creates a direct path for credential theft without requiring any elevation of privilege exploits or authentication bypasses beyond standard login credentials.
The operational impact of this vulnerability is severe due to the potential for repository compromise and supply chain attacks. An attacker with read access can extract the private signing key and subsequently use it to sign malicious packages, updates, or metadata within that YUM repository. Since package managers rely on digital signatures to verify the integrity and authenticity of software sources, an adversary possessing a valid signature from a trusted repository can inject malware into the distribution stream. This effectively allows the attacker to compromise all systems configured to trust that specific repository, leading to widespread unauthorized code execution across enterprise environments relying on Red Hat Enterprise Linux, CentOS, Fedora, or other YUM-based distributions.
This vulnerability aligns with CWE-798: Use of Hard-coded Credentials and CWE-200: Exposure of Sensitive Information to an Unauthorized Actor within the Common Weakness Enumeration framework. From a tactical perspective, it facilitates initial access and persistence in attack scenarios described by MITRE ATT&CK techniques such as T1552.004: Private Keys or T1608.003: Install Digital Certificate if leveraged to establish trust for further malicious activities. The ability to sign artifacts under a trusted identity undermines the fundamental security guarantees provided by package management systems, making this a high-severity issue requiring immediate remediation.
Mitigation strategies should prioritize restricting access to repository configuration endpoints that expose sensitive metadata. Administrators must ensure that only users with explicit write or administrative privileges can view private key configurations. Sonatype has addressed this in subsequent releases of Nexus Repository 3 by implementing stricter authorization checks on the relevant API calls. Organizations running affected versions are advised to upgrade immediately to a patched version where these access controls have been corrected. Additionally, as a precautionary measure, any private keys potentially exposed through this vulnerability should be considered compromised and rotated out of use across all dependent systems to prevent further exploitation by malicious actors who may have already harvested the data.