GCD AI RADAR
incidents/AIR-2026-0596

CVE-2026-39861: Claude Code Sandbox Escape via Symlink

Attack on AI2 Disclosed vulnerabilityInfrastructure vulnerability

Claude Code permitted sandboxed processes to create symlinks outside the workspace, causing unsandboxed operations to write to arbitrary locations. This enabled a sandbox escape and potential code execution.

disclosed CVENo confirmed exploitation, so this record is tracked as a disclosed vulnerability and not counted as an incident. It moves into the counts if CISA or the vendor confirms exploitation. Why

Details

type
Attack on AI
An AI model, agent or AI-powered product was the thing exploited, abused or leaked.
categories
  • Infrastructure vulnerability
    CVEs and advisories in AI frameworks, inference servers, MCP servers, AI developer tools and hosting stacks.
owasp llm top 10
mitre atlas
no technique for these categories
Both rows are derived from the type and categories (OWASP 2025 edition, ATLAS release 2026.09), not classified per record. How
severity
2 · Disclosed vulnerability
CVE or vendor advisory, patched or patchable, no confirmed exploitation.
targets
Anthropic, Framework / tooling
products
Claude Code
incident date
21 Apr 2026
first reported
21 Apr 2026
origin
GitHub Advisory Database
Vulnerability record from NVD / the GitHub Advisory Database. This product uses the NVD API but is not endorsed or certified by the NVD.
classifier confidence
0.95 · published at or above 0.80; see the methodology
tags
CVE-2026-39861 · sandbox-escape
record
created 2026-10-18 07:00Z · updated 2026-10-18 10:04Z · json

Sources · 2

  1. 2026-04-21
    CVE-2026-39861: Claude Code: Sandbox Escape via Symlink Following Allows Arbitrary File Write Outside Workspace
    GitHub Advisory Database · github.com/advisories/GHSA-vp62-r36r-9xqp
  2. 2026-04-21
    CVE-2026-39861: Claude Code is an agentic coding tool.
    NVD · nvd.nist.gov/vuln/detail/CVE-2026-39861

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