CVE-2026-41373: OpenClaw RCE Vulnerability

CVE-2026-41373 Overview

OpenClaw before version 2026.3.31 contains an incomplete host-env-security-policy.json configuration that fails to restrict compiler binary environment variables. This vulnerability allows untrusted models to substitute critical compiler environment variables including CC, CXX, CARGO_BUILD_RUSTC, and CMAKE_C_COMPILER via environment overrides. Attackers with approved host-exec requests can leverage this flaw to override compiler binaries and execute arbitrary code during build processes.

Critical Impact
Attackers can execute arbitrary code by substituting compiler binaries during build processes through unrestricted environment variable overrides.

Affected Products

OpenClaw versions prior to 2026.3.31

Discovery Timeline

2026-04-28 - CVE CVE-2026-41373 published to NVD
2026-04-28 - Last updated in NVD database

Technical Details for CVE-2026-41373

Vulnerability Analysis

This vulnerability is classified as CWE-427 (Uncontrolled Search Path Element), where the security policy configuration fails to properly restrict environment variables that control compiler binary paths. The incomplete host-env-security-policy.json policy omitted critical compiler-related environment variables from its blocklist, creating a gap in the security sandbox.

When untrusted models execute build processes through approved host-exec requests, they can inject malicious values for compiler environment variables. Since build systems like Make, CMake, and Cargo rely on these environment variables to locate compiler binaries, an attacker can redirect compilation to execute arbitrary malicious binaries instead of legitimate compilers.

The attack requires local access and an approved host-exec request, which limits the attack surface but still poses a significant risk in multi-tenant or shared build environments where untrusted code may be compiled.

Root Cause

The root cause is an incomplete security policy configuration in host-env-security-policy.json. The original policy blocked various dangerous environment variables related to Git, shell configuration, and other utilities, but failed to include compiler-related environment variables in its blocklist. This oversight allowed the CC, CXX, CARGO_BUILD_RUSTC, CMAKE_C_COMPILER, and CMAKE_CXX_COMPILER variables to be overridden by untrusted models.

Attack Vector

An attacker with an approved host-exec request can exploit this vulnerability by:

Setting malicious values for compiler environment variables (CC, CXX, CARGO_BUILD_RUSTC, CMAKE_C_COMPILER)
Triggering a build process that relies on these environment variables
The build system invokes the attacker-controlled binary instead of the legitimate compiler
Arbitrary code execution occurs with the privileges of the build process

The following patch adds the missing compiler environment variables to the security policy blocklist:

text

     "GIT_EXEC_PATH",
     "GIT_SEQUENCE_EDITOR",
     "GIT_TEMPLATE_DIR",
+    "CC",
+    "CXX",
+    "CARGO_BUILD_RUSTC",
+    "CMAKE_C_COMPILER",
+    "CMAKE_CXX_COMPILER",
     "SHELL",
     "SHELLOPTS",
     "PS4",

Source: GitHub Commit Reference

Detection Methods for CVE-2026-41373

Indicators of Compromise

Unexpected values set for CC, CXX, CARGO_BUILD_RUSTC, CMAKE_C_COMPILER, or CMAKE_CXX_COMPILER environment variables during build processes
Build logs showing compiler binary paths pointing to non-standard locations
Unusual process spawning patterns during compilation operations
Evidence of environment variable manipulation in host-exec request logs

Detection Strategies

Monitor environment variable assignments during host-exec requests for compiler-related variables
Implement logging for all build process invocations and verify compiler binary paths match expected locations
Deploy file integrity monitoring on known compiler binary locations
Audit host-exec request approvals and track which environment variables are being set

Monitoring Recommendations

Enable verbose logging for all host-exec requests and build operations
Configure alerts for environment variable overrides targeting CC, CXX, CARGO_BUILD_RUSTC, CMAKE_C_COMPILER, or CMAKE_CXX_COMPILER
Review build process audit logs for anomalous compiler binary invocations
Implement runtime monitoring for unexpected process execution during compilation

How to Mitigate CVE-2026-41373

Immediate Actions Required

Upgrade OpenClaw to version 2026.3.31 or later immediately
Review recent host-exec requests for any suspicious environment variable overrides
Audit build logs for evidence of compiler binary substitution
Temporarily restrict host-exec permissions until the patch is applied

Patch Information

The vulnerability has been addressed in OpenClaw version 2026.3.31. The fix adds CC, CXX, CARGO_BUILD_RUSTC, CMAKE_C_COMPILER, and CMAKE_CXX_COMPILER to the blocked environment variables list in host-env-security-policy.json. The patch is available via commit e277a37f896b5011a1df06e6490c6630074d0afa.

For additional details, refer to the GitHub Security Advisory and the VulnCheck Advisory.

Workarounds

Manually add the missing compiler environment variables to your host-env-security-policy.json blocklist if immediate upgrade is not possible
Restrict host-exec request approvals to trusted sources only
Implement additional access controls around build processes
Consider running builds in isolated environments with fixed compiler paths

bash

# Verify OpenClaw version
openclaw --version

# Check if your security policy includes compiler env blocks
grep -E "(CC|CXX|CARGO_BUILD_RUSTC|CMAKE_C_COMPILER|CMAKE_CXX_COMPILER)" /path/to/host-env-security-policy.json