Anthropic Claude CLI OS Command Injection via TERMINAL Variable
CVE-2026-35020 Published on April 6, 2026
Anthropic Claude Code & Agent SDK OS Command Injection via TERMINAL Environment Variable
Anthropic Claude Code CLI and Claude Agent SDK contain an OS command injection vulnerability in the command lookup helper and deep-link terminal launcher that allows local attackers to execute arbitrary commands by manipulating the TERMINAL environment variable. Attackers can inject shell metacharacters into the TERMINAL variable which are interpreted by /bin/sh when the command lookup helper constructs and executes shell commands with shell=true. The vulnerability can be triggered during normal CLI execution as well as via the deep-link handler path, resulting in arbitrary command execution with the privileges of the user running the CLI.
Vulnerability Analysis
CVE-2026-35020 is exploitable with local system access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2026-35020. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
What is a Shell injection Vulnerability?
The software constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
CVE-2026-35020 has been classified to as a Shell injection vulnerability or weakness.
Products Associated with CVE-2026-35020
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Affected Versions
Anthropic Claude Code:- Before and including 2.1.91 is affected.
- Before and including 0.1.55 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.