CVE-2026-39861
Critical · 10.0CVSS
10.0
EPSS
0.8%
Published
Apr 21, 2026
CISA due date
—
The record
Claude Code is an agentic coding tool. Prior to version 2.1.64, Claude Code's sandbox did not prevent sandboxed processes from creating symlinks pointing to locations outside the workspace. When Claude Code subsequently wrote to a path within such a symlink, its unsandboxed process followed the symlink and wrote to the target location outside the workspace without prompting the user for confirmation. This allowed a sandbox escape where neither the sandboxed command nor the unsandboxed app could independently write outside the workspace, but their combination could write to arbitrary locations, potentially leading to code execution outside the sandbox. Reliably exploiting this required the ability to add untrusted content into a Claude Code context window to trigger sandboxed code execution via prompt injection. Users on standard Claude Code auto-update have received this fix automatically. Users performing manual updates are advised to update to version 2.1.64 or later.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| npm | @anthropic-ai/claude-code | 0 | 2.1.64 |
Related vulnerabilities
- GHSA-vp62-r36r-9xqp Claude Code: Sandbox Escape via Symlink Following Allows Arbitrary File Write Outside… Same vulnerability
- CVE-2026-54316 Claude Code is an agentic coding tool. Also affects @anthropic-ai/claude-code
- GHSA-fg94-h982-f3mm Claude Code: Out-of-Band Data Exfiltration via Pre-Approved HuggingFace Domain in WebFetch Also affects @anthropic-ai/claude-code
- CVE-2026-40068 In versions 2.1.63 through 2.1.83 of Claude Code, the folder trust determination logic… Also affects @anthropic-ai/claude-code
- GHSA-q5hj-mxqh-vv77 Claude Code: Trust Dialog Bypass via Git Worktree Spoofing Allows Arbitrary Code Execution Also affects @anthropic-ai/claude-code
- GHSA-5cwg-9f6j-9jvx Claude Code: Insecure System-Wide Configuration Loading Enables Local Privilege… Also affects @anthropic-ai/claude-code
- CVE-2026-35603 Claude Code is an agentic coding tool. Also affects @anthropic-ai/claude-code
- CVE-2026-33068 Claude Code is an agentic coding tool. Also affects @anthropic-ai/claude-code