CVE-2026-42435

HighPublic PoC

Published: 05 May 2026

Published

05 May 2026

Modified

05 May 2026

KEV Added

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Patch

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CVSS Score 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Score 0.0011 28.5th percentile

Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-42435 is a high-severity Incomplete List of Disallowed Inputs (CWE-184) vulnerability. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Unix Shell (T1059.004); ranked at the 28.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 RA-5 (Vulnerability Monitoring and Scanning) and SI-10 (Information Input Validation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Unix Shell (T1059.004) and 2 other techniques. What defenders deploy: see the NIST 800-53 controls recommended below.

Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

SI-2 Flaw Remediation good match

prevent

Requires timely identification, reporting, and correction of flaws like the shell-wrapper detection bypass via patching to OpenClaw 2026.4.12 or later.

SI-10 Information Input Validation good match

prevent

Enforces validation of argv inputs to prevent injection of environment variable assignments that bypass exec preflight handling.

RA-5 Vulnerability Monitoring and Scanning good match

detect

Mandates vulnerability scanning to identify deployments of vulnerable OpenClaw versions affected by CVE-2026-42435.

MITRE ATT&CK Enterprise TechniquesAI

T1059.004 Unix Shell Execution

Adversaries may abuse Unix shell commands and scripts for execution.

attack.mitre.org →

T1068 Exploitation for Privilege Escalation Privilege Escalation

Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.

attack.mitre.org →

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

Why these techniques?

Vulnerability enables direct manipulation of Unix shell variables (SHELLOPTS/PS4) via argv injection to bypass wrapper protections, directly facilitating Unix shell command execution (T1059.004). Low-privilege network exploitation yielding full C/I/A impact maps to exploitation for privilege escalation (T1068). Network-accessible flaw in application service enables exploitation of public-facing application (T1190).

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

OpenClaw versions from 2026.2.22 before 2026.4.12 contain an insufficient shell-wrapper detection vulnerability allowing attackers to inject environment variable assignments at the argv level. Attackers can bypass exec preflight handling to manipulate high-risk shell variables like SHELLOPTS and PS4, affecting execution…

semantics and security controls.

Deeper analysisAI

CVE-2026-42435 is an insufficient shell-wrapper detection vulnerability affecting OpenClaw versions from 2026.2.22 before 2026.4.12. The flaw enables attackers to inject environment variable assignments at the argv level, bypassing exec preflight handling and allowing manipulation of high-risk shell variables such as SHELLOPTS and PS4. This impacts execution semantics and security controls. The vulnerability carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and maps to CWE-184.

Attackers with low privileges (PR:L) can exploit this over the network (AV:N) with low attack complexity (AC:L) and no user interaction (UI:N). Exploitation bypasses shell-wrapper protections, enabling manipulation of shell variables to alter execution behavior, achieve high impacts on confidentiality, integrity, and availability (C:H/I:H/A:H), and undermine security controls.

Mitigation is addressed in OpenClaw version 2026.4.12 and later, as evidenced by the fixing commit at https://github.com/openclaw/openclaw/commit/8f8492d172f4c5b4fd7dd9a47855ed620c8770ab. Additional details are provided in the GitHub security advisory at https://github.com/openclaw/openclaw/security/advisories/GHSA-j6c7-3h5x-99g9 and the VulnCheck advisory at https://www.vulncheck.com/advisories/openclaw-shell-wrapper-detection-bypass-via-environment-variable-assignment-injection.