Sonatype Nexus Repository Security Advisory
Date: June 20th, 2016
Affected Versions: All previous Nexus Repository OSS/Pro versions up to and including 2.11.1
Fixed in Version: Nexus Repository OSS/Pro version 2.11.2-01
Risk: High - 8.1 (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)
A remote code execution has been discovered in Nexus Repository 2 requiring immediate action. The vulnerability allows for an unauthenticated attacker with network access to perform remote code exploits. We have mitigated the issue through instructions provided by the upstream library authors, and they have fixed the vulnerability (CVE-2016-4437) in their library. This advisory provides the pertinent information needed to properly address this vulnerability, along with the details on how to reach us if you have any further questions or concerns.
This vulnerability was identified by an external researcher and has been verified by our security team. We are not aware of any active exploits taking advantage of this issue. However, we strongly encourage all users of Nexus to immediately take the steps outlined in this advisory.
The identified vulnerability can trigger deserialization of any Java classes from libraries included in the Nexus Repository instance. A remote attacker could use this flaw in combination with libraries vulnerable to deserialization attacks to execute arbitrary code with the permissions of the application. We are highly recommending all instances of Nexus Repository be upgraded to 2.11.2-01 or later.
Publicly available Nexus Repository 2 instances are at greater risk and we have taken steps to mitigate this vulnerability in known public forge instances as well as providing remediation guidance to the overall Nexus Repository user community.
The vulnerability associated with this advisory is fixed in Nexus 2.11.2-01 and above.
For detailed information on upgrade compatibility, please see:
If you run into any problems, or have any questions/concerns, please contact us by filing a ticket at https://support.sonatype.com.
Frequently Asked Questions:
Q: What is the risk associated with this vulnerability?
A: Nexus can be compromised, allowing an unauthenticated attacker to use the flaw in combination with libraries vulnerable to deserialization attacks on the instance.
Q: What preconditions must be met in order to be vulnerable?
A: An attacker must have network access to the Nexus Repository instance.
Q: Are there implications associated with this advisory itself?
A: Disclosure unfortunately means bad actors may try to take advantage. While we have initially limited the information to the minimum details necessary for users to affect an appropriate fix, this merely slows down a would be attacker. As such, we are advising all organizations utilizing Nexus Repository to immediately assess their individual impact and take appropriate action in response.
Q: Where can I obtain more information associated with the vulnerability?
A: At this time, and in the interest of best protecting our user community, we are limiting the information released to that absolutely required in order to assess impact and affect remediation. Please contact support for more information.
Q: Why is Sonatype making this information available?
A: This is part of a responsible disclosure process. Given Nexus Repository is an open source project with over 100,000 active server installations, notifying the user base will invariably lead to broad dissemination. We are taking a concerted and proactive approach in our outreach activities and an effort to achieve the most rapid remediation possible.