CVE-2026-34450 Claude SDK for Python: Insecure Default File Permissions in Local Filesystem Memory Tool
Local attackers can read or modify agent memory files due to insecure default permissions in the Anthropic Python SDK.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-34450?
CVE-2026-34450 is a medium-severity vulnerability in anthropics anthropic-sdk-python, published on 31 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
The Claude SDK for Python provides access to the Claude API from Python applications. From version 0.86.0 to before version 0.87.0, the local filesystem memory tool in the Anthropic Python SDK created memory files with mode 0o666, leaving them world-readable on systems with a standard umask and world-writable in environments with a permissive umask such as many Docker base images. A local attacker on a shared host could read persisted agent state, and in containerized deployments could modify memory files to influence subsequent model behavior. Both the synchronous and asynchronous memory tool implementations were affected. This issue has been patched in version 0.87.0.
Which versions are affected by CVE-2026-34450?
3 open source packages ship an affected version, including anthropic. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
anthropic PyPI | From 0.86.0 | 0.87.0 |
anthropic PyPI | From 0.86.0 | 0.87.0 |
anthropic PyPI | From 0.86.0 | 0.87.0 |
Products include Anthropic Claude Sdk for Python.
How do I fix CVE-2026-34450?
Upgrade anthropic to 0.87.0 or later.
Is CVE-2026-34450 being exploited?
There is no known exploitation of CVE-2026-34450 in the wild and no public exploit code.
Other vulnerabilities in anthropics anthropic-sdk-python
Sources
Also known as ECHO-3bbc-736a-5aa2, GHSA-q5f5-3gjm-7mfm, PYSEC-2026-2114.