CVE-2026-32981: Anyscale Ray Path Traversal Vulnerability

CVE-2026-32981 Overview

A path traversal vulnerability was identified in the Ray Dashboard (default port 8265) in Anyscale Ray versions prior to 2.8.1. Due to improper validation and sanitization of user-supplied paths in the static file handling mechanism, an attacker can use traversal sequences (e.g., ../) to access files outside the intended static directory, resulting in local file disclosure.

This vulnerability is classified as CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), a common weakness that allows attackers to bypass access controls and read sensitive files from the server filesystem.

Critical Impact

Unauthenticated attackers with network access to the Ray Dashboard can read arbitrary files from the server filesystem, potentially exposing sensitive configuration files, credentials, API keys, and other confidential data used in machine learning workloads.

Affected Products

• Anyscale Ray versions prior to 2.8.1
• Ray Dashboard component (default port 8265)
• All deployments with network-accessible Ray Dashboard instances

Discovery Timeline

• 2026-03-17 - CVE-2026-32981 published to NVD
• 2026-03-19 - Last updated in NVD database

Technical Details for CVE-2026-32981

Vulnerability Analysis

The vulnerability resides in the Ray Dashboard's static file handling mechanism. When processing requests for static resources, the application fails to properly validate and sanitize user-supplied path components. This oversight allows attackers to inject directory traversal sequences such as ../ into file path requests, enabling them to escape the intended static file directory and access arbitrary files on the underlying filesystem.

The Ray Dashboard, which serves as the web-based management interface for Ray clusters, exposes this vulnerability through its HTTP endpoint on port 8265. Since Ray is commonly deployed in data science and machine learning environments, compromised systems may contain highly sensitive intellectual property, training data, model weights, and cloud credentials.

Root Cause

The root cause of this vulnerability is insufficient input validation in the static file serving functionality of the Ray Dashboard. The application accepts user-controlled path input without adequately checking for or neutralizing path traversal sequences. When a request containing ../ sequences is processed, the file path resolution occurs relative to the filesystem root rather than being constrained to the intended static assets directory.

The absence of path canonicalization and proper boundary checks allows attackers to construct malicious requests that reference files outside the web application's document root, including system configuration files, application secrets, and user data.

Attack Vector

The attack vector is network-based and requires no authentication or user interaction. An attacker with network connectivity to the Ray Dashboard (port 8265) can craft HTTP requests containing path traversal sequences to read arbitrary files.

A typical exploitation scenario involves sending crafted HTTP GET requests to the static file endpoint with traversal sequences designed to escape the static directory. By manipulating the path parameter with sequences like ../../../etc/passwd or ../../../home/user/.aws/credentials, an attacker can systematically enumerate and exfiltrate sensitive files from the target system.

The attack is particularly dangerous in cloud and containerized environments where configuration files often contain secrets, API keys, and database credentials that could enable lateral movement or data exfiltration.

Detection Methods for CVE-2026-32981

Indicators of Compromise

• HTTP requests to the Ray Dashboard containing path traversal sequences (../, ..%2f, ..%252f)
• Access log entries showing requests for system files (e.g., /etc/passwd, /etc/shadow, credential files)
• Unusual volume of requests to static file endpoints on port 8265
• Failed file access attempts followed by successful reads of system files
• Network connections to Ray Dashboard from unexpected external IP addresses

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block path traversal patterns in URL paths
• Configure intrusion detection systems (IDS) with signatures for directory traversal attack patterns
• Implement anomaly detection on Ray Dashboard access logs to identify suspicious file access patterns
• Monitor file access events on sensitive system files for reads originating from the Ray Dashboard process

Monitoring Recommendations

• Enable detailed access logging on Ray Dashboard instances and forward logs to a SIEM platform
• Establish baseline file access patterns and alert on deviations indicating potential exploitation
• Monitor network traffic to port 8265 for connections from untrusted networks or IP ranges
• Implement real-time alerting for any requests containing encoded traversal sequences

How to Mitigate CVE-2026-32981

Immediate Actions Required

• Upgrade Anyscale Ray to version 2.8.1 or later to obtain the security patch
• Restrict network access to the Ray Dashboard (port 8265) to trusted IP addresses only
• Implement a reverse proxy with WAF capabilities to filter malicious requests before they reach the Dashboard
• Review Ray Dashboard access logs for evidence of prior exploitation attempts
• Audit systems for unauthorized file access or data exfiltration

Patch Information

Anyscale has addressed this vulnerability in Ray version 2.8.1. Organizations running affected versions should upgrade immediately. The fix implements proper path validation and sanitization to ensure that file requests cannot escape the intended static file directory.

For additional technical details, refer to the VulnCheck Path Traversal Advisory and the Ray Project GitHub Repository.

Workarounds

• Implement network segmentation to prevent untrusted network access to the Ray Dashboard
• Deploy a reverse proxy (e.g., nginx, Apache) with rules to block requests containing traversal patterns
• Use firewall rules to limit access to port 8265 to authorized management hosts only
• Consider disabling the Ray Dashboard entirely if it is not required for operations
• Enable authentication mechanisms if supported by your Ray deployment configuration

# Example: Restrict Ray Dashboard access using iptables
# Allow access only from trusted management network (10.0.0.0/24)
iptables -A INPUT -p tcp --dport 8265 -s 10.0.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 8265 -j DROP