Executive Summary

CVE-2026-27523 is a vulnerability in OpenClaw versions prior to 2026.2.24 that allows attackers to bypass sandbox bind mount validation. The issue arises because the software does not properly handle symlinked parent directories when the final leaf path component does not exist. Attackers can craft bind source paths that appear to be within allowed root directories but actually resolve outside the sandbox boundaries once the missing leaf components are created. This happens because the validation only canonicalized paths if the full source path existed, missing cases where symlink parents point outside allowed roots or into blocked paths.

The vulnerability weakens the enforcement of sandbox isolation by allowing path traversal through symlinks combined with missing leaf nodes, effectively bypassing allowed-root and blocked-path checks.

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Impact Analysis

This vulnerability can impact you by allowing an attacker with limited privileges to escape sandbox restrictions. By exploiting the symlink and missing leaf path issue, an attacker can mount or bind paths that appear safe but actually point outside the intended sandbox environment.

This can lead to unauthorized access to sensitive files or directories outside the sandbox, potentially resulting in integrity violations (modifying or injecting malicious data) and availability issues (disrupting expected sandbox behavior).

The CVSS v3.1 score of 6.1 and v4.0 score of 6.9 reflect a moderate severity, indicating a significant risk especially in environments relying on sandbox isolation for security.

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Compliance Impact

I don't know

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Detection Guidance

[{'type': 'paragraph', 'content': 'Detection of this vulnerability involves identifying bind mounts in OpenClaw that use symlinked parent directories with non-existent leaf paths, which can bypass sandbox bind validation.'}, {'type': 'paragraph', 'content': 'Since the vulnerability exploits symlink paths where the final leaf does not exist, you can check for bind mounts with source paths that include symlinks and verify if those paths resolve outside allowed sandbox roots once missing leaf components are created.'}, {'type': 'paragraph', 'content': 'Suggested commands to help detect such conditions include:'}, {'type': 'list_item', 'content': 'Use `find` to locate symlinks in bind mount source directories: `find /path/to/bind/source -type l`'}, {'type': 'list_item', 'content': 'Use `readlink -f` or `realpath` on bind source paths to resolve their canonical paths and check if they lie outside allowed roots: `realpath /path/to/bind/source`'}, {'type': 'list_item', 'content': "Check for missing leaf components by verifying if the full bind source path exists: `test -e /path/to/bind/source || echo 'Missing leaf component'`"}, {'type': 'paragraph', 'content': 'By combining these checks, you can identify bind mounts that may be vulnerable to this bypass by confirming if symlinked parents resolve outside allowed directories once missing leaf nodes are created.'}] [1, 2]

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Mitigation Strategies

The immediate mitigation step is to upgrade OpenClaw to version 2026.2.24 or later, where the vulnerability has been fixed.

The fix strengthens sandbox bind mount validation by resolving bind source paths through their deepest existing ancestor directories, preventing bypasses via symlinked parents with missing leaf nodes.

If upgrading immediately is not possible, consider auditing and restricting bind mounts to ensure no symlinked parent directories with missing leaf components are used, and avoid allowing bind mounts from untrusted or complex symlinked paths.

Additionally, monitor and block bind mounts that resolve outside allowed source roots or into blocked paths by implementing stricter path validation in your sandbox configuration.

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