CVE-2026-34450: Claude SDK for Python: Insecure Default File Permissions in Local Filesystem Memory Tool
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.
Other sources
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.
Users on the affected versions are advised to update to the latest version.
Claude SDK for Python thanks lucasfutures on HackerOne for the report.
— GitHub
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
pip/anthropicto a version that resolves this vulnerability.Fixed in 0.87.0 - Upgrade
Upgrade
Anthropic Python SDK (Claude SDK for Python)to a version that resolves this vulnerability.Fixed in 0.87.0 - Configuration
Update to 0.87.0, which patches the local filesystem memory tool that previously created memory files with mode 0o666.
Local filesystem memory tool (Anthropic Python SDK) memory files permission mode = 0o666 (world-readable/world-writable)
Event History
Frequently Asked Questions
What is the severity of CVE-2026-34450?
CVE-2026-34450 has been classified as a medium severity vulnerability due to insecure default file permissions.
How do I fix CVE-2026-34450?
To fix CVE-2026-34450, upgrade to the version 0.87.0 or later of the Claude SDK for Python.
What settings are affected by CVE-2026-34450?
CVE-2026-34450 affects the local filesystem memory tool used by the Claude SDK for Python.
In which versions of the Claude SDK does CVE-2026-34450 exist?
CVE-2026-34450 exists in the Claude SDK for Python from version 0.86.0 to before version 0.87.0.
What can happen if CVE-2026-34450 is exploited?
If CVE-2026-34450 is exploited, unauthorized access to sensitive files may occur due to insecure file permissions.