CVE-2026-32977: Openclaw Race Condition Vulnerability

CVE-2026-32977 Overview

OpenClaw before version 2026.3.11 contains a sandbox boundary bypass vulnerability in the fs-bridge writeFile commit step that uses an unanchored container path during the final move operation. An attacker can exploit a time-of-check-time-of-use (TOCTOU) race condition by modifying parent paths inside the sandbox to redirect committed files outside the validated writable path within the container mount namespace.

Critical Impact

This vulnerability allows local attackers with low privileges to bypass sandbox boundaries and write files to unauthorized locations within the container mount namespace, potentially compromising container integrity and availability.

Affected Products

• OpenClaw versions prior to 2026.3.11
• OpenClaw for Node.js environments

Discovery Timeline

• 2026-03-31 - CVE-2026-32977 published to NVD
• 2026-04-02 - Last updated in NVD database

Technical Details for CVE-2026-32977

Vulnerability Analysis

This vulnerability is classified as CWE-367 (Time-of-Check Time-of-Use Race Condition). The core issue resides in the fs-bridge component's writeFile commit step, where the system performs path validation and the actual file write operation as separate, non-atomic steps.

The fs-bridge module validates that the target path is within the allowed writable sandbox directory. However, between this validation check and the final move operation, there exists a window where an attacker can manipulate the parent directory paths. By exploiting this race condition, malicious actors can redirect the file write operation to locations outside the intended sandbox boundary.

The attack requires local access and low privileges, but does not require user interaction. When successfully exploited, the vulnerability enables high-impact integrity and availability violations, though confidentiality remains unaffected. The unanchored path handling during the commit step fails to re-validate the resolved path immediately before the write, creating the exploitable TOCTOU gap.

Root Cause

The root cause lies in the improper synchronization between path validation and file operations within the fs-bridge writeFile commit mechanism. The implementation uses an unanchored container path during the final move operation, meaning the resolved path is not re-verified against sandbox boundaries at the moment of the actual file write. This architectural flaw creates a race window that can be exploited through rapid path manipulation.

Attack Vector

The attack vector is local, requiring the attacker to have authenticated access to the system with low-level privileges. The exploitation technique involves:

1. Initiating a legitimate file write operation within the sandbox
2. During the window between path validation and the commit operation, rapidly modifying parent directory symlinks or paths
3. Redirecting the committed file to a location outside the validated writable path
4. Achieving file writes to unauthorized container locations

The vulnerability manifests in the file commit workflow where path resolution occurs non-atomically. For detailed technical analysis, see the GitHub Security Advisory or the VulnCheck Security Advisory.

Detection Methods for CVE-2026-32977

Indicators of Compromise

• Unusual file write operations targeting paths outside expected sandbox directories
• Rapid modifications to directory symlinks within container mount namespaces
• Unexpected file creation in sensitive system directories within containers
• Audit logs showing file operations that bypass normal sandbox validation patterns

Detection Strategies

• Monitor for rapid sequential operations involving directory path modifications followed by file commits
• Implement file integrity monitoring (FIM) on critical paths outside sandbox boundaries
• Deploy runtime application self-protection (RASP) to detect TOCTOU race condition exploitation patterns
• Enable detailed logging of fs-bridge operations to identify anomalous write patterns

Monitoring Recommendations

• Configure container runtime security tools to alert on unexpected file system modifications
• Implement SentinelOne Singularity for real-time behavioral detection of sandbox escape attempts
• Monitor process activity for suspicious patterns of symlink manipulation followed by file operations
• Review fs-bridge commit logs for operations that resolve to unexpected final paths

How to Mitigate CVE-2026-32977

Immediate Actions Required

• Upgrade OpenClaw to version 2026.3.11 or later immediately
• Review container configurations to ensure minimal privilege assignment
• Audit recent file operations within affected containers for potential exploitation
• Implement additional file system monitoring on critical paths

Patch Information

The vendor has released a security patch addressing this vulnerability. Update to OpenClaw version 2026.3.11 or later, which implements atomic path validation and commit operations. For complete patch details, refer to the GitHub Security Advisory.

Workarounds

• Restrict local access to systems running vulnerable OpenClaw versions
• Implement strict file system permissions to limit symlink creation within sandbox directories
• Consider running OpenClaw containers with read-only root filesystems where possible
• Deploy additional security monitoring to detect race condition exploitation attempts

# Configuration example - Restrict symlink creation in sandbox
# Add to container security profile
chmod o-w /path/to/sandbox/
chattr +i /path/to/sandbox/critical_dirs/

# Enable audit logging for fs-bridge operations
auditctl -w /path/to/sandbox -p wa -k openclaw_sandbox_monitor