CVE-2020-29436 Nexus Repository 3 and IQ Server - XML External Entities injection - 2020-12-15

Date:  December 15th, 2020

Affected Versions:  

  • All previous Nexus Repository 3 OSS/Pro versions up to and including 3.28.1
  • IQ Server from release 74 up to and including release 101

Fixed in Version:  

  • Nexus Repository OSS/Pro version 3.29.0
  • IQ Server release 102


Critical - 8.7 (CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:H)


An XML External Entities (XXE) injection vulnerability has been discovered in Nexus Repository 3 requiring immediate action. The vulnerability allows an attacker with an administrative account in Nexus Repository 3 to configure the system in a way that allows them to view files on the filesystem, and to interact with any back-end or external systems that Nexus Repository 3 can access. We have mitigated the issue by no longer allowing the XML parsing library to process these external entities. 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 externally and has been verified by our security team. We are not aware of any active exploits taking advantage of this issue.


We are highly recommending all affected instances of Nexus Repository 3 be upgraded to Nexus Repository 3.29.0 or later. The latest version can be downloaded from:

For detailed information on upgrade, please see:

Upgrading Nexus Repository Manager 3.1.0 and Newer

We are highly recommending all affected instances of IQ Server be upgraded to release 102 or later. The latest version can be downloaded from:


This issue was discovered and reported by James Mills at F-Secure Consulting.


If you run into any problems or have any questions/concerns, please contact us by filing a ticket at

Frequently Asked Questions:

Q:  What is the risk associated with this vulnerability?

A:  Nexus Repository 3 can be compromised, allowing an attacker to read and potentially modify any content on the system that the Nexus Repository 3 server has access to.


Q: What preconditions must be met in order to be vulnerable?

A: An attacker must have an administrative-level user account in the Nexus Repository 3 instance to configure the system in this manner.


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 Manager 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 what 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 3 is an open-source project with widespread usage, notifying the user base will invariably lead to broad dissemination.  We are taking a concerted and proactive approach in our outreach activities and in an effort to achieve the most rapid remediation possible.

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