CVE-2026-4040 Overview
A vulnerability has been identified in OpenClaw versions up to 2026.2.17. This issue affects the function tools.exec.safeBins within the File Existence Handler component. The manipulation of this function leads to information exposure through discrepancy, classified under CWE-200 (Information Exposure). The attack requires local access to the system.
Critical Impact
Local attackers can exploit timing or behavioral discrepancies in the safeBins function to determine the existence of sensitive files, potentially leaking information about system configuration or file structures.
Affected Products
- OpenClaw versions up to 2026.2.17
- OpenClaw File Existence Handler component
- Systems using the tools.exec.safeBins function
Discovery Timeline
- 2026-03-12 - CVE-2026-4040 published to NVD
- 2026-03-12 - Last updated in NVD database
Technical Details for CVE-2026-4040
Vulnerability Analysis
This vulnerability falls into the Information Disclosure category, specifically information exposure through discrepancy. The tools.exec.safeBins function in the File Existence Handler component does not properly mask its responses when checking for file existence. This creates an observable difference in behavior that allows a local attacker to determine whether specific files exist on the system.
Information exposure through discrepancy vulnerabilities occur when an application's response behavior differs based on the presence or absence of protected resources. In this case, the safeBins function likely exhibits timing differences, error message variations, or response pattern changes that reveal file existence information to unauthorized users.
Root Cause
The root cause lies in improper handling of file existence checks within the tools.exec.safeBins function. The function fails to normalize its responses, creating detectable differences that leak information about the underlying file system structure. This implementation does not follow secure coding practices that require consistent response behavior regardless of whether a queried resource exists.
Attack Vector
The attack must be performed locally on the affected system. An attacker with local access can systematically query the safeBins function to map out file structures and determine the existence of sensitive configuration files, binaries, or other resources. This information can then be leveraged for further attacks or reconnaissance activities.
The vulnerability mechanism involves observing discrepancies in how the File Existence Handler responds to queries for existing versus non-existing files. The attacker can probe the system by:
- Making multiple requests to the safeBins function with different file paths
- Observing response timing, error messages, or behavioral patterns
- Correlating the responses to determine which files exist on the system
For technical implementation details, see the GitHub Security Advisory.
Detection Methods for CVE-2026-4040
Indicators of Compromise
- Unusual patterns of file existence queries through the tools.exec.safeBins function
- Repeated rapid calls to the File Existence Handler component from the same source
- Log entries showing systematic probing of file paths through the affected function
Detection Strategies
- Monitor for abnormal access patterns to the tools.exec.safeBins function
- Implement logging for all file existence checks performed by the File Existence Handler
- Review application logs for sequential queries attempting to enumerate file structures
Monitoring Recommendations
- Enable verbose logging for the OpenClaw File Existence Handler component
- Set up alerts for unusual volume of calls to tools.exec.safeBins
- Audit local user access and privileges on systems running vulnerable OpenClaw versions
How to Mitigate CVE-2026-4040
Immediate Actions Required
- Upgrade OpenClaw to version 2026.2.19-beta.1 or later
- Review and audit systems for potential exploitation of the file enumeration vulnerability
- Restrict local access to systems running vulnerable versions until patching is complete
Patch Information
The vulnerability has been addressed in OpenClaw version 2026.2.19-beta.1. The fix is tracked by commit bafdbb6f112409a65decd3d4e7350fbd637c7754. Organizations should upgrade to the patched version to remediate this vulnerability.
Additional resources:
Workarounds
- Limit local access to systems running vulnerable OpenClaw versions to trusted users only
- Implement additional access controls around the File Existence Handler component
- Consider disabling or restricting the tools.exec.safeBins function if not required for operations
# Upgrade OpenClaw to the patched version
# Replace with your package manager commands as appropriate
cd /path/to/openclaw
git fetch --tags
git checkout v2026.2.19-beta.1
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
