Is this vulnerability remotely exploitable?

It can be, but only in contexts where an attacker can reliably inject content into a Claude Code context and steer sandboxed code execution (such as through prompt injection or compromised project assets). The vulnerability itself is local to the machine running Claude Code but can be triggered indirectly by remote input.

What level of access does an attacker need to exploit this?

The attacker must be able to provide untrusted content that Claude Code will interpret in a way that causes the sandboxed environment to create or manipulate symlinks and then induce the unsandboxed application to perform writes to those paths. Direct shell access is not required, but effective control over sandboxed commands is.

What is the safest general fix pattern for this class of issue?

The most robust pattern is to resolve all file paths to their canonical form before performing operations and then verify that the resolved paths remain within the intended sandbox or workspace directory, rejecting or warning on any attempt to step outside. Complement this with restrictions on symlink creation and strict permission separation between sandboxed and unsandboxed components.

Severity:

CRITICAL RISK

(10.0)

Sandbox Symlink Workspace Escape (CWE-22/CWE-61) in Claude Code

CVE-2026-39861

Published:

Apr 20, 2026

Status:

Analyzed

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

NDV

Recent Vulnerabilities

CWE-74;CWE-89

HIGH RISK

HIGH

(7.3)

SQL Injection via Unsanitized ID Parameter (CWE-89) in Pharmacy Sales and Inventory System /ajax.php

Database Compromise and Data Integrity Loss

April 27, 2026

CWE-863

HIGH RISK

HIGH

(8.5)

Incorrect Authorization (CWE-863) in OpenClaw chat.send Session Management

Privilege Escalation and Unauthorized Session Control

April 27, 2026

Vulnerability Type

Category:

Sandbox Escape via Symlink Path Traversal

CWE:

CWE-22;CWE-61

Impact:

Arbitrary File Write and Potential Code Execution Outside Sandbox

Severity:

CRITICAL RISK

(10.0)

CVSS Version:

3.1

Vulnerability Type

Category:

Sandbox Escape via Symlink Path Traversal

CWE:

CWE-22;CWE-61

Impact:

Arbitrary File Write and Potential Code Execution Outside Sandbox

Severity:

CRITICAL RISK

(10.0)

CVSS Version:

3.1

Catch This CVE While Code Is Being Written

Detect vulnerable code directly in pull requests, so CVEs are fixed before merge.

Get Started

Ship clean & secure code faster

START 14 DAYS FREE TRIAL

BOOK A DEMO

Made with Love in San Francisco

355 Bryant St. San Francisco, CA 94107, USA

Ask AI for summary of CodeAnt

Made with Love in San Francisco

355 Bryant St. San Francisco, CA 94107, USA

Ask AI for summary of CodeAnt

Made with Love in San Francisco

355 Bryant St. San Francisco, CA 94107, USA

Ask AI for summary of CodeAnt

Sandbox Symlink Workspace Escape (CWE-22/CWE-61) in Claude Code

Summary

Affected Context

Exploit Preconditions

Why This Happens

Potential Impact

General Mitigation Guidance

How Teams Detect Issues Like This

Frequently Asked Questions

Source

Recent Vulnerabilities

HIGH RISK

HIGH

(7.3)

SQL Injection via Unsanitized ID Parameter (CWE-89) in Pharmacy Sales and Inventory System /ajax.php

HIGH RISK

HIGH

(8.5)

Incorrect Authorization (CWE-863) in OpenClaw chat.send Session Management

Vulnerability Type

Vulnerability Type

Vulnerability Type

Catch This CVE While Code Is Being Written

Ship clean & secure code faster

Product

Pricing

Company

Legal

Developers

Compare

Product

Pricing

Company

Legal

Developers

Compare

Product

Pricing

Company

Legal

Developers

Compare