Executive Summary

CVE-2026-42435 is a vulnerability in OpenClaw versions from 2026.2.22 before 2026.4.12 where the shell-wrapper detection mechanism is insufficient. This flaw allows attackers to inject environment variable assignments directly at the argv level, bypassing exec preflight handling.

By exploiting this, attackers can manipulate high-risk shell variables such as SHELLOPTS and PS4, which can alter the execution semantics and undermine security controls, potentially leading to command injection attacks.

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Impact Analysis

This vulnerability can have a significant impact by allowing attackers to bypass security checks and inject malicious environment variable assignments. This manipulation can change how shell commands are executed, potentially leading to unauthorized command execution or escalation of privileges.

Because critical shell variables like SHELLOPTS and PS4 can be controlled, attackers may alter execution behavior and security controls, increasing the risk of system compromise.

The vulnerability has a high severity score (CVSS v3.1 BaseScore 8.8), indicating a serious risk to confidentiality, integrity, and availability.

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Detection Guidance

This vulnerability involves insufficient detection of shell-wrapper invocations that allow environment variable assignment injection at the argv level. Detection involves identifying commands or processes that invoke shell wrappers with environment variable assignments embedded in their arguments.

To detect this vulnerability on your system or network, you should monitor command executions for suspicious environment variable assignments in argv forms, especially those manipulating high-risk shell variables like SHELLOPTS and PS4.

While no explicit detection commands are provided in the resources, you can use system auditing or process monitoring tools to look for command lines invoking shell wrappers (e.g., sh, bash, env, nice, busybox) with environment variable assignments. For example, on Linux systems, you might use commands like:

• ps aux | grep -E '(env|sh|bash|nice|busybox)'
• auditctl rules to monitor execve syscalls and log commands with environment variable assignments
• Using tools like sysdig or strace to trace process executions and inspect argv arguments for environment variable assignments

Additionally, reviewing logs or telemetry for commands that manipulate SHELLOPTS, PS4, or other shell environment variables in unusual ways can help detect exploitation attempts.

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Mitigation Strategies

The primary mitigation step is to upgrade OpenClaw to version 2026.4.12 or later, as this version includes patches that enhance shell-wrapper detection and block environment variable assignment injection attacks.

The patch includes improved detection of shell-wrapper invocations, stricter validation of environment variable overrides, and blocking of unsafe environment variable assignments in command arguments.

Until you can upgrade, consider restricting or monitoring the use of shell wrappers and environment variable assignments in command invocations, especially those that could manipulate high-risk shell variables like SHELLOPTS and PS4.

Implementing stricter execution policies and auditing command executions can help reduce the risk of exploitation.

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Compliance Impact

The provided information does not specify any direct impact of CVE-2026-42435 on compliance with common standards and regulations such as GDPR or HIPAA.

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