CVE-2026-3067: Hummerrisk Path Traversal Vulnerability

CVE-2026-3067 Overview

A path traversal vulnerability has been discovered in HummerRisk, an open-source cloud-native security platform. This vulnerability affects the extractTarGZ and extractZip functions within the CommandUtils.java file located in the hummer-common/hummer-common-core/src/main/java/com/hummer/common/core/utils/ component. The flaw allows attackers to manipulate archive extraction operations to write files outside the intended directory, potentially leading to arbitrary file write conditions on the target system.

Critical Impact

Remote attackers with low privileges can exploit this path traversal vulnerability to extract malicious files to arbitrary locations on the server, potentially overwriting critical system files or planting malicious payloads.

Affected Products

• HummerRisk versions up to 1.5.0
• hummer-common-core component
• Archive Extraction functionality in CommandUtils.java

Discovery Timeline

• 2026-02-24 - CVE-2026-3067 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2026-3067

Vulnerability Analysis

This path traversal vulnerability (CWE-22) exists in HummerRisk's archive extraction functionality. The extractTarGZ and extractZip functions in CommandUtils.java fail to properly sanitize file paths contained within compressed archives before extraction. When processing user-supplied archive files, the application does not validate whether extracted file paths contain directory traversal sequences such as ../ or absolute paths that could escape the intended extraction directory.

The vulnerability is remotely exploitable with low attack complexity, requiring only low-level privileges. An attacker can craft a malicious archive containing files with path traversal sequences in their filenames. When the vulnerable application extracts this archive, files are written to locations outside the designated extraction directory, potentially allowing the attacker to overwrite configuration files, inject malicious code, or compromise system integrity.

Root Cause

The root cause of this vulnerability is insufficient input validation in the archive extraction logic. The extractTarGZ and extractZip functions do not implement proper path canonicalization or containment checks to ensure that extracted file paths remain within the intended target directory. This allows specially crafted archive entries with relative path components to escape the extraction boundary.

Attack Vector

This vulnerability can be exploited remotely over the network. An authenticated attacker with low privileges can upload or provide a malicious archive file to the HummerRisk application. The attack requires no user interaction and can be executed with low complexity.

The attack flow involves:

1. The attacker crafts a malicious TAR.GZ or ZIP archive containing files with path traversal sequences in their filenames (e.g., ../../etc/cron.d/malicious)
2. The attacker submits this archive to the HummerRisk application through a feature that triggers archive extraction
3. The vulnerable extractTarGZ or extractZip function processes the archive without validating file paths
4. Files are extracted to arbitrary locations on the filesystem, potentially overwriting critical system or application files

For technical details and proof-of-concept information, refer to the GitHub Issue Discussion.

Detection Methods for CVE-2026-3067

Indicators of Compromise

• Unexpected files appearing in system directories outside normal application paths
• Modified configuration files or system cron jobs that were not administratively changed
• Log entries showing archive extraction operations followed by file writes to sensitive directories
• Presence of files with timestamps matching archive extraction events in unauthorized locations

Detection Strategies

• Monitor file system activity for write operations to sensitive directories (e.g., /etc/, application configuration directories) originating from the HummerRisk Java process
• Implement file integrity monitoring (FIM) on critical system files and directories to detect unauthorized modifications
• Analyze application logs for archive extraction operations involving suspicious filenames containing ../ sequences
• Deploy runtime application self-protection (RASP) solutions to detect and block path traversal attempts

Monitoring Recommendations

• Enable verbose logging for HummerRisk archive extraction operations to capture all processed file paths
• Configure alerts for any file creation or modification events in system directories that originate from the HummerRisk application context
• Implement network traffic analysis to identify uploads of potentially malicious archive files

How to Mitigate CVE-2026-3067

Immediate Actions Required

• Restrict access to HummerRisk features that allow archive file uploads or processing to trusted administrators only
• Implement network segmentation to limit the potential impact of exploitation
• Review system directories for any unauthorized files that may have been written via exploitation
• Consider temporarily disabling archive extraction functionality until a patch is available

Patch Information

At the time of publication, the vendor (HummerRisk) has not responded to disclosure attempts and no official patch is available. Organizations should monitor the VulDB entry and the official HummerRisk repository for security updates. The exploit has been publicly disclosed, increasing the risk of exploitation in the wild.

Workarounds

• Implement a web application firewall (WAF) rule to block archive uploads containing files with path traversal patterns
• Apply filesystem permissions to restrict the HummerRisk application's write access to only necessary directories
• Deploy container-based isolation for HummerRisk to limit the blast radius of potential path traversal exploitation
• Consider implementing a file upload proxy that sanitizes archive contents before forwarding to HummerRisk

Organizations should apply defense-in-depth strategies until an official patch becomes available from the vendor.