CVE-2022-27907: Nexus Repository Manager SSRF Flaw

CVE-2022-27907 Overview

CVE-2022-27907 is a Server-Side Request Forgery (SSRF) vulnerability in Sonatype Nexus Repository Manager 3.x versions prior to 3.38.0. Authenticated users with low privileges can coerce the server into issuing HTTP requests to attacker-chosen destinations. The flaw maps to CWE-918: Server-Side Request Forgery. Sonatype addressed the issue in version 3.38.0 and published guidance in their Sonatype Support Article.

Critical Impact

Authenticated attackers can abuse the repository manager to reach internal services, metadata endpoints, or otherwise unreachable network resources, enabling reconnaissance and limited information disclosure.

Affected Products

• Sonatype Nexus Repository Manager 3.x prior to 3.38.0
• Deployments exposing the Nexus web interface or REST API to networked users
• Self-hosted Nexus instances integrated with internal CI/CD networks

Discovery Timeline

• 2022-03-30 - CVE-2022-27907 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-27907

Vulnerability Analysis

The vulnerability is a Server-Side Request Forgery condition in the Nexus Repository Manager 3 web application. An authenticated user with low privileges can submit a request that causes the Nexus server to initiate an outbound HTTP request to a URL controlled by the attacker. Because the request originates from the Nexus host, it can reach internal-only assets that the attacker cannot contact directly. The confidentiality impact is limited, and there is no direct impact to integrity or availability of the Nexus instance itself.

Root Cause

The root cause is insufficient validation of user-supplied URLs or remote resource identifiers within Nexus Repository Manager 3.x. Server-side fetch logic accepts destinations without restricting them to expected hosts, schemes, or network ranges. Sonatype shipped corrected validation in release 3.38.0.

Attack Vector

Exploitation requires network access to the Nexus web interface or API and valid low-privileged credentials. The attacker submits a crafted request that includes an attacker-controlled URL in a parameter consumed by a server-side fetch routine. Nexus then performs the outbound request, and the attacker observes responses or side effects. Refer to the Sonatype Support Article for the authoritative technical description.

No public proof-of-concept code has been verified for this CVE. The vulnerability mechanism is described in prose above; readers seeking exploit specifics should consult vendor advisories rather than rely on synthetic samples.

Detection Methods for CVE-2022-27907

Indicators of Compromise

• Outbound HTTP or HTTPS connections from the Nexus host to unexpected external domains or internal RFC1918 addresses.
• Nexus access logs containing authenticated requests with URL parameters pointing to non-repository hosts.
• Connections from the Nexus server to cloud metadata endpoints such as 169.254.169.254.

Detection Strategies

• Inspect Nexus application logs for low-privileged user activity that includes URL parameters referencing internal or metadata hosts.
• Correlate Nexus process network telemetry with allowed upstream repository hosts and alert on deviations.
• Compare the running Nexus version against 3.38.0 to identify exposed instances.

Monitoring Recommendations

• Forward Nexus audit and access logs to a centralized SIEM and build queries for SSRF patterns in URL parameters.
• Monitor egress traffic from CI/CD infrastructure for connections to unexpected destinations.
• Track authentication events for low-privileged accounts that perform unusual API operations.

How to Mitigate CVE-2022-27907

Immediate Actions Required

• Upgrade Sonatype Nexus Repository Manager 3 to version 3.38.0 or later.
• Audit user accounts and remove unnecessary low-privileged access to the Nexus API.
• Restrict outbound network access from the Nexus host to only required repository upstreams.

Patch Information

Sonatype resolved CVE-2022-27907 in Nexus Repository Manager 3.38.0. Operators should follow the upgrade procedure documented in the Sonatype Support Article. Verify the deployed version after upgrade and confirm that integrations continue to function against the patched build.

Workarounds

• Place the Nexus instance behind an egress proxy that allow-lists only legitimate upstream repositories.
• Block outbound access from the Nexus host to cloud metadata services such as 169.254.169.254.
• Enforce network segmentation so the Nexus server cannot reach sensitive internal management interfaces.

# Example iptables egress restriction blocking cloud metadata access from the Nexus host
iptables -A OUTPUT -d 169.254.169.254 -j DROP
iptables -A OUTPUT -p tcp --dport 80 -m owner --uid-owner nexus -d 10.0.0.0/8 -j DROP
iptables -A OUTPUT -p tcp --dport 443 -m owner --uid-owner nexus -d 10.0.0.0/8 -j DROP