CVE-2026-3048 Overview
CVE-2026-3048 affects Sonatype Nexus Repository Manager versions 3.0.0 through 3.91.1. An authenticated administrator who configures or tests Lightweight Directory Access Protocol (LDAP) connectivity may initiate unintended server-side connections when interacting with a malicious LDAP server. The vulnerability is mapped to [CWE-502] (Deserialization of Untrusted Data) and requires high privileges to exploit. Sonatype addressed the issue in Nexus Repository version 3.92.0.
Critical Impact
Authenticated administrators connecting Nexus Repository to a malicious LDAP server can trigger unintended server-side interactions, potentially exposing low-impact confidentiality and integrity risks on the Nexus host.
Affected Products
- Sonatype Nexus Repository Manager 3.0.0 through 3.91.1
- Self-hosted Nexus Repository deployments using LDAP authentication
- Administrator-accessible LDAP configuration and test endpoints
Discovery Timeline
- 2026-05-11 - CVE-2026-3048 published to NVD
- 2026-05-13 - Last updated in NVD database
Technical Details for CVE-2026-3048
Vulnerability Analysis
The flaw resides in the LDAP configuration and connectivity-test workflow exposed to authenticated administrators in Nexus Repository Manager. When an administrator points the LDAP client at a server URL, the application establishes a server-side connection and processes responses returned by that LDAP service. A malicious LDAP server can return crafted responses that the Nexus LDAP client handles in unsafe ways, mapped by Sonatype to [CWE-502] (Deserialization of Untrusted Data).
Because the connection originates from the Nexus host, an attacker controlling the remote LDAP endpoint can influence how Nexus parses and reacts to attributes returned during bind, search, or referral operations. The CVSS v4.0 vector indicates limited confidentiality and integrity impact and no availability impact, with no impact to subsequent systems.
Root Cause
The root cause is improper handling of attacker-controlled data returned by an arbitrary LDAP server during configuration or connectivity testing. The Nexus LDAP client processes server-supplied content without sufficient validation, allowing untrusted data to influence application behavior on the server side.
Attack Vector
Exploitation requires an authenticated user with administrative privileges and the ability to point Nexus at an attacker-controlled LDAP endpoint. The attacker must operate a malicious LDAP service reachable from the Nexus host. No user interaction outside the admin workflow is required, and the attack is performed over the network.
No public proof-of-concept code is available for CVE-2026-3048. Refer to the Sonatype Support Article for vendor-supplied technical detail.
Detection Methods for CVE-2026-3048
Indicators of Compromise
- Outbound LDAP or LDAPS connections from Nexus Repository hosts to unknown or external IP addresses on TCP 389, 636, or non-standard LDAP ports.
- Audit log entries showing LDAP realm configuration changes or connectivity tests initiated by administrator accounts at unusual times.
- Unexpected DNS resolutions from the Nexus server for domains not associated with the organization's directory infrastructure.
Detection Strategies
- Review Nexus Repository audit logs for LDAP configuration create, update, or test events and correlate with the source administrator account.
- Inspect host-level process and network telemetry on the Nexus server for new outbound LDAP sessions following administrative actions.
- Compare configured LDAP server hostnames against an allow-list of approved directory services and alert on deviations.
Monitoring Recommendations
- Enable verbose audit logging in Nexus Repository and forward logs to a centralized analytics platform for retention and correlation.
- Restrict egress firewall rules so the Nexus host can only reach approved LDAP servers, and alert on blocked connection attempts.
- Monitor administrator account activity for anomalous configuration changes, including LDAP realm additions and test invocations.
How to Mitigate CVE-2026-3048
Immediate Actions Required
- Upgrade Sonatype Nexus Repository Manager to version 3.92.0 or later as documented in the Sonatype Release Notes.
- Audit existing LDAP realm configurations and remove any pointing to untrusted or unrecognized servers.
- Enforce least privilege on administrative accounts and rotate credentials for any admin who may have tested unverified LDAP endpoints.
Patch Information
Sonatype released Nexus Repository Manager 3.92.0 to remediate CVE-2026-3048. See the Sonatype Release Notes and the Sonatype Support Article for upgrade guidance and version coverage.
Workarounds
- Restrict administrative access to Nexus Repository to a small set of trusted operators with multi-factor authentication.
- Block outbound LDAP traffic from the Nexus host at the network perimeter except to explicitly approved directory servers.
- Disable or avoid the LDAP connectivity-test workflow against external endpoints until the upgrade to 3.92.0 is applied.
# Example egress restriction limiting Nexus host to an approved LDAP server
# Replace 10.10.0.25 with your authorized LDAP server IP
iptables -A OUTPUT -p tcp -d 10.10.0.25 --dport 636 -j ACCEPT
iptables -A OUTPUT -p tcp --dport 389 -j REJECT
iptables -A OUTPUT -p tcp --dport 636 -j REJECT
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
