CVE-2026-40515: OpenHarness Permission Bypass Vulnerability

CVE-2026-40515 Overview

OpenHarness before commit bd4df81 contains a permission bypass vulnerability that allows attackers to read sensitive files by exploiting incomplete path normalization in the permission checker. This authorization bypass vulnerability (CWE-863) enables attackers to invoke the built-in grep and glob tools with sensitive root directories that are not properly evaluated against configured path rules, allowing disclosure of sensitive local file content, key material, configuration files, or directory contents despite configured path restrictions.

Critical Impact

Attackers can bypass permission controls to read sensitive files including cryptographic key material, configuration files, and directory contents from protected paths on affected OpenHarness installations.

Affected Products

• OpenHarness versions before commit bd4df81f634f8c7cddcc3fdf7f561a13dcbf03ae

Discovery Timeline

• 2026-04-17 - CVE-2026-40515 published to NVD
• 2026-04-17 - Last updated in NVD database

Technical Details for CVE-2026-40515

Vulnerability Analysis

This vulnerability stems from an authorization bypass weakness (CWE-863: Incorrect Authorization) in OpenHarness's permission checking mechanism. The permission checker fails to properly normalize file paths when evaluating access requests made through the built-in grep and glob tools.

When users invoke these tools with root directory arguments, the permission checker does not adequately evaluate the paths against configured path restrictions. This creates a gap between the intended security policy and the actual enforcement, allowing unauthorized file access operations to succeed.

The vulnerability is particularly dangerous because it affects core file access tools within the OpenHarness framework, potentially exposing sensitive data such as private keys, database credentials, API tokens, and system configuration files that administrators believed were protected.

Root Cause

The root cause lies in incomplete path normalization within the permission checker component. When the grep and glob tools receive directory arguments, the permission validation logic fails to properly resolve and evaluate the full path hierarchy against the configured access rules. This allows attackers to craft requests that bypass the intended file access restrictions by exploiting the discrepancy between how paths are specified and how they are validated.

Attack Vector

This vulnerability is exploitable over the network without requiring authentication or user interaction. An attacker can send specially crafted requests to an OpenHarness instance, invoking the grep or glob tools with arguments pointing to sensitive directories. Due to the incomplete path normalization, these requests bypass the permission checker and return contents of files or directories that should be restricted.

The attack flow involves:

1. Identifying an accessible OpenHarness endpoint
2. Crafting requests using the grep or glob tools with sensitive root directory paths
3. The permission checker fails to properly evaluate the path against configured restrictions
4. Sensitive file contents or directory listings are returned to the attacker

For detailed technical information, see the VulnCheck Security Advisory and the GitHub Pull Request #92.

Detection Methods for CVE-2026-40515

Indicators of Compromise

• Unexpected file access requests targeting sensitive directories such as /etc/, /root/, or application configuration paths via grep or glob tools
• Log entries showing successful file reads from paths that should be restricted by permission policies
• Unusual access patterns to files containing credentials, keys, or configuration data
• Evidence of directory enumeration through the glob tool against protected paths

Detection Strategies

• Monitor and audit all requests to the grep and glob tool endpoints for suspicious path arguments
• Implement application-layer logging to capture full request details including file paths accessed
• Configure alerts for access attempts to known sensitive directories or file patterns
• Review access logs for successful reads of files in restricted directories

Monitoring Recommendations

• Enable verbose logging for the OpenHarness permission checker component
• Set up real-time alerts for file access operations targeting sensitive paths
• Implement file integrity monitoring on critical configuration files and key material
• Conduct periodic audits of access logs to identify potential exploitation attempts

How to Mitigate CVE-2026-40515

Immediate Actions Required

• Update OpenHarness to commit bd4df81f634f8c7cddcc3fdf7f561a13dcbf03ae or later immediately
• Audit access logs to determine if the vulnerability has been exploited
• Rotate any credentials or key material that may have been exposed
• Review and tighten file permission configurations as an additional layer of defense

Patch Information

The vulnerability has been addressed in OpenHarness commit bd4df81f634f8c7cddcc3fdf7f561a13dcbf03ae. The fix corrects the path normalization logic in the permission checker to properly evaluate all path arguments against configured access rules.

For patch details, see the GitHub Commit Update.

Workarounds

• Restrict network access to OpenHarness instances to trusted sources only until patching is complete
• Disable or restrict access to the grep and glob tools if they are not required for operations
• Implement additional access controls at the network or reverse proxy layer to filter requests with sensitive path arguments
• Consider running OpenHarness with minimal file system permissions to limit potential exposure