CVE-2025-66479 Anthropic Sandbox Runtime Incorrectly Implemented Network Sandboxing
Sandboxed code can bypass network restrictions if no allowed domains are configured, allowing unauthorized network access.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-66479?
CVE-2025-66479 is a low-severity vulnerability in anthropic-experimental sandbox-runtime, published on 4 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Anthropic Sandbox Runtime is a lightweight sandboxing tool for enforcing filesystem and network restrictions on arbitrary processes at the OS level, without requiring a container. Prior to 0.0.16, due to a bug in sandboxing logic, sandbox-runtime did not properly enforce a network sandbox if the sandbox policy did not configure any allowed domains. This could allow sandboxed code to make network requests outside of the sandbox. A patch for this was released in v0.0.16.
Weakness: CWE-693
Which versions are affected by CVE-2025-66479?
2 open source packages ship an affected version, including @anthropic-ai/sandbox-runtime.
| Package | Affected | Fixed in |
|---|---|---|
@anthropic-ai/sandbox-runtime npm | All versions | 0.0.16 |
@anthropic-ai/sandbox-runtime npm | All versions | 0.0.16 |
How do I fix CVE-2025-66479?
Upgrade @anthropic-ai/sandbox-runtime to 0.0.16 or later.
Is CVE-2025-66479 being exploited?
There is no known exploitation of CVE-2025-66479 in the wild and no public exploit code.
Sources
Also known as GHSA-9gqj-5w7c-vx47.