CVE-2026-55799: Apache Ranger RCE Vulnerability

CVE-2026-55799 Overview

CVE-2026-55799 is a remote code execution vulnerability in the GraalScriptEngineCreator component of Apache Ranger versions up to and including 2.8.0. The flaw stems from improper control of code generation [CWE-94] within the Graal script engine integration. Attackers can execute arbitrary code on affected Ranger deployments over the network without authentication or user interaction. Apache has released version 2.9.0 to remediate the issue.

Apache Ranger provides centralized authorization, auditing, and data governance for Hadoop ecosystems. A compromise of Ranger can undermine access control decisions across every integrated data platform.

Critical Impact
Unauthenticated attackers can achieve full remote code execution on Apache Ranger servers, breaking authorization enforcement across the entire data platform.

Affected Products

Apache Ranger versions <= 2.8.0
GraalScriptEngineCreator component within Apache Ranger
Hadoop and data platforms that rely on Apache Ranger for authorization

Discovery Timeline

2026-08-10 - CVE-2026-55799 published to NVD
2026-08-12 - Last updated in NVD database

Technical Details for CVE-2026-55799

Vulnerability Analysis

The vulnerability resides in the GraalScriptEngineCreator class used by Apache Ranger to evaluate script-based policy conditions. Ranger allows administrators to define fine-grained authorization policies that include scripted context enrichment and conditional logic. The Graal-based engine executes these scripts to make runtime authorization decisions.

The implementation fails to properly sandbox script execution and does not sufficiently restrict host access or Java class loading. Untrusted input reaching the script evaluation path is interpreted as executable code rather than sanitized data. This condition is classified under [CWE-94] Improper Control of Generation of Code, commonly referred to as code injection.

A successful attack yields code execution in the context of the Ranger service account. This account typically has privileged access to policy stores, audit databases, and integrations with HDFS, Hive, HBase, Kafka, and other data services.

Root Cause

The root cause is missing isolation between untrusted policy or request data and the Graal script engine execution context. The engine is instantiated without a restrictive HostAccess policy or class filter, allowing scripts to reach arbitrary Java classes and reflection APIs. Any attacker-influenced input that reaches script evaluation can invoke Runtime.exec or equivalent primitives.

Attack Vector

The attack vector is network-based and requires no privileges or user interaction. An attacker sends crafted requests to a Ranger endpoint that triggers script-based policy evaluation. The malicious payload is interpreted by the Graal engine and executes on the server. Refer to the Apache Mailing List Thread and the Openwall OSS-Security Post for the vendor advisory. No verified public exploit code is available at the time of publication.

Detection Methods for CVE-2026-55799

Indicators of Compromise

Unexpected child processes spawned by the Apache Ranger Java process, particularly shells such as sh, bash, or cmd.exe.
Outbound network connections initiated from the Ranger service host to unfamiliar IP addresses or ports.
Anomalous entries in Ranger admin logs referencing script evaluation errors, GraalScriptEngineCreator, or reflection classes.
New or modified files under Ranger installation directories that were not deployed by administrators.

Detection Strategies

Hunt for process lineage where the Ranger JVM is the parent of interpreter or shell processes.
Alert on Java processes loading java.lang.Runtime or ProcessBuilder classes through Graal script contexts.
Inspect Ranger REST API traffic for policy condition payloads containing script keywords or Java class references.

Monitoring Recommendations

Forward Ranger admin, audit, and JVM logs to a centralized SIEM for correlation.
Baseline outbound connectivity from Ranger hosts and alert on deviations.
Monitor policy modification events for unexpected additions of scripted conditions.

How to Mitigate CVE-2026-55799

Immediate Actions Required

Upgrade Apache Ranger to version 2.9.0 on every Ranger admin and plugin host.
Restrict network access to Ranger administrative interfaces using firewall rules and allowlists.
Rotate credentials, tokens, and keys accessible to the Ranger service account after patching.
Review recent policy changes for unauthorized scripted conditions and remove them.

Patch Information

Apache has fixed this vulnerability in Apache Ranger 2.9.0. Users running any version at or below 2.8.0 must upgrade. Consult the Apache Mailing List Thread for the official announcement and release notes.

Workarounds

If upgrade is not immediately possible, disable script-based policy conditions across all Ranger services.
Isolate Ranger admin endpoints behind an authenticated reverse proxy accessible only to administrators.
Run the Ranger service under a least-privilege account with no shell, restricted filesystem access, and no outbound internet.

bash

# Verify installed Apache Ranger version and upgrade path
ranger-admin version
# Expected after remediation: Apache Ranger 2.9.0 or later