CVE-2026-34450: anthropic claude_sdk_for_python Incorrect Default Permissions

Vulnerability summary

CVE-2026-34450 is a medium (CVSS 4.8) Incorrect Default Permissions vulnerability in anthropic claude_sdk_for_python. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6.4% of scored vulnerabilities.

Timeline

1. 31-03-2026
   PublishedVulnerability first disclosed.
2. 01-04-2026
   Last modifiedVulnerability information updated.

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.

• CWE-276Incorrect Default PermissionsDuring installation, installed file permissions are set to allow anyone to modify those files.
• CWE-732Incorrect Permission Assignment for Critical ResourceThe product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.