CVE-2026-42537: Apache Ranger RCE Vulnerability

CVE-2026-42537 Overview

CVE-2026-42537 is a remote code execution vulnerability in Apache Ranger versions up to and including 2.8.0. The flaw stems from improper input validation [CWE-20] in the handling of Java Database Connectivity (JDBC) URLs. Attackers can inject crafted JDBC connection strings that trigger code execution on the underlying host. The Apache Software Foundation released Apache Ranger 2.9.0 to remediate the issue. The vulnerability is exploitable over the network, requires no authentication, and needs no user interaction.

Critical Impact
Unauthenticated attackers can achieve remote code execution on servers running Apache Ranger, compromising centralized authorization for Hadoop ecosystem data platforms.

Affected Products

Apache Ranger versions <= 2.8.0
Deployments integrating Ranger with Hadoop, Hive, HBase, Kafka, and related big-data services
Downstream distributions bundling vulnerable Ranger releases

Discovery Timeline

2026-08-10 - CVE-2026-42537 published to NVD
2026-08-12 - Last updated in NVD database

Technical Details for CVE-2026-42537

Vulnerability Analysis

Apache Ranger provides centralized authorization, auditing, and data security across the Hadoop ecosystem. The affected code path accepts JDBC URL parameters without adequate validation. Attackers can supply a malicious connection string that references attacker-controlled classes or drivers. When Ranger initiates the JDBC connection, the crafted URL triggers execution of arbitrary code within the server process.

The issue is classified as Improper Input Validation [CWE-20]. Successful exploitation grants the attacker code execution in the context of the Ranger service account, which typically holds elevated privileges over policy enforcement across integrated data platforms.

Root Cause

The root cause is missing sanitization of user-supplied JDBC URL fields. JDBC drivers such as those for MySQL, PostgreSQL, and H2 support connection properties that can load classes, execute initialization SQL, or reference remote resources. Without allowlisting hosts, drivers, and properties, Ranger passes attacker-controlled URLs directly to DriverManager.getConnection(), enabling code execution primitives common to JDBC injection attacks.

Attack Vector

An unauthenticated remote attacker sends a crafted request to a Ranger endpoint that consumes a JDBC URL. By embedding malicious properties, such as autoDeserialize=true combined with a controlled queryInterceptors class or an H2 INIT script, the attacker forces the server to load and execute arbitrary Java code. Refer to the Apache Mailing List Thread and Openwall OSS Security Discussion for advisory details.

No verified public proof-of-concept code was available at the time of writing. See the referenced advisories for technical background.

Detection Methods for CVE-2026-42537

Indicators of Compromise

Outbound network connections from Ranger hosts to unexpected database endpoints or LDAP/RMI servers.
Unusual Java child processes spawned by the Ranger service account, including sh, bash, cmd.exe, or powershell.exe.
New or modified JAR files, class files, or scheduled tasks appearing on Ranger admin servers.
Ranger audit or application logs containing JDBC URL parameters with suspicious properties such as INIT, queryInterceptors, or autoDeserialize.

Detection Strategies

Inspect HTTP request bodies to Ranger admin endpoints for JDBC URL fields containing jdbc:h2:, jdbc:mysql:// with property overrides, or references to remote hosts.
Alert on Java processes owned by the Ranger service invoking shell or scripting interpreters, which indicate post-exploitation activity.
Correlate Ranger audit events with endpoint telemetry to identify anomalous authorization service behavior.

Monitoring Recommendations

Enable verbose logging on Ranger admin APIs and forward logs to a SIEM for JDBC-parameter analysis.
Monitor egress traffic from Ranger hosts and restrict outbound connectivity to known database endpoints.
Baseline normal parent-child process relationships for the Ranger JVM and alert on deviations.

How to Mitigate CVE-2026-42537

Immediate Actions Required

Upgrade Apache Ranger to version 2.9.0 or later on all admin and plugin hosts.
Restrict network access to the Ranger admin UI and APIs to trusted management networks only.
Rotate credentials stored in Ranger configurations if compromise is suspected.
Review Ranger audit logs since deployment for suspicious JDBC URL submissions.

Patch Information

The Apache Ranger project fixed this issue in version 2.9.0. Operators running any release at or below 2.8.0 must upgrade. Consult the Apache Mailing List Thread for the official announcement and upgrade guidance.

Workarounds

Place Ranger admin services behind a reverse proxy that strips or validates JDBC URL parameters before forwarding requests.
Enforce network segmentation so Ranger hosts cannot reach arbitrary external hosts on database or Java Naming and Directory Interface (JNDI) ports.
Run the Ranger service under a least-privilege account with no shell access and restricted filesystem permissions.

bash

# Verify installed Apache Ranger version and plan upgrade
rpm -qa | grep -i ranger
# Or when installed from tarball
cat /opt/ranger/version || grep version /opt/ranger/ews/webapp/META-INF/MANIFEST.MF
# Restrict admin UI exposure at the firewall
iptables -A INPUT -p tcp --dport 6080 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 6080 -j DROP