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The vulnerability, identified in OpenClaw versions up to 2026.2.25, is a sandbox bypass caused by improper validation of symbolic links (symlinks) during boundary checks . Specifically, the flaw resides in how the application handles “dangling symlink hops”—symlinks that point to non-existent targets. Under certain conditions, particularly during workspace-only write operations like apply_patch, the boundary validation logic would incorrectly treat these symlink paths as remaining within the sandbox root. This occurred because the system failed to fully resolve the canonical path through existing directory ancestors when the immediate symlink target was missing. An attacker could exploit this by crafting a scenario where a symlink within the workspace points to a location outside the workspace root. When a write operation follows this symlink, the path traversal is not detected, allowing files to be written to arbitrary locations on the host system, thereby breaking the integrity of the sandbox . The fix implemented in commit `4fd29a3` addresses this by resolving symlink targets through existing ancestor paths and ensuring the operation fails closed if the canonical resolution escapes the configured boundary.
dailycve form:
Platform: OpenClaw/npm
Version: <=2026.2.25
Vulnerability: Sandbox bypass
Severity: High
date: February 26, 2026
Prediction: 2026.2.26
What Undercode Say:
Analytics
- Vulnerability Discovery: The issue was reported externally by security researcher @tdjackey, highlighting the importance of community-driven security audits for open-source package managers .
- Affected Component: The core flaw resides in the path resolution logic for workspace-only write flows, specifically within functions like `apply_patch` that handle file operations inside a sandboxed environment.
- Root Cause: The primary weakness is a “boundary-validation gap” where the system fails to canonicalize paths through existing directory structures when encountering a dangling symlink, leading to an incorrect assessment of the path’s containment.
- Fix Strategy: The patch implements a more robust resolution process by walking up the directory tree (“through existing ancestors”) to determine the real path and enforces a “fail-closed” state if that path breaches the sandbox.
- Impact Scope: While confidentiality is not the primary concern, the integrity of the host system is at high risk, as an attacker could potentially overwrite critical configuration files or inject malicious code into other applications by writing outside the intended workspace .
Exploit:
Scenario: An attacker-controlled process or a malicious workspace configuration. Assumption: The target workspace has a directory structure that allows symlink creation. 1. Inside the workspace, create a directory that will contain a symlink. mkdir -p ./workspace/write_target 2. Create a symlink named 'config' that points to a sensitive file outside the workspace. For example, the system's hosts file or an application config. ln -s /etc/passwd ./workspace/write_target/config 3. Trigger a workspace write operation (e.g., apply_patch) that writes to the path './workspace/write_target/config'. Due to the vulnerability, the boundary check sees the path as './workspace/write_target/config' but does not fully resolve the symlink to '/etc/passwd'. The write operation then follows the symlink, resulting in writing content to /etc/passwd. The exact command to trigger the vulnerable write path would depend on the specific OpenClaw API or CLI command being used, such as: openclaw apply_patch --input malicious.patch --target ./workspace/write_target/config
Protection from this CVE
- Immediate Patching: The most effective protection is to update OpenClaw to version `2026.2.26` or later, which contains the fix for the symlink resolution logic .
- Input Validation: As a defense-in-depth measure, applications using OpenClaw should implement strict validation on all file paths before they are passed to workspace write operations, ensuring that resolved paths do not contain directory traversal sequences (
..) and remain within the intended base directory. - Filesystem Hardening: Employ filesystem-level access controls (e.g., mandatory access control with AppArmor or SELinux) to restrict the OpenClaw process from writing to sensitive system directories, even if a path traversal or symlink attack succeeds.
Impact
The primary impact of this vulnerability is a violation of filesystem integrity. An attacker with the ability to control or influence workspace write operations (such as patch application) can break out of the intended sandbox and write data to arbitrary locations on the host system. This could lead to:
– Data Corruption: Overwriting critical system or application files.
– Privilege Escalation: If the attacker can write to directories or files used by higher-privileged processes (e.g., writing a cron job or modifying a service’s configuration), it could lead to code execution with elevated privileges.
– Denial of Service: Overwriting critical system files could render the operating system or key applications inoperable.
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Sources:
Reported By: github.com
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