CVE-2026-34450 MEDIUM

CVE-2026-34450: Claude SDK for Python: Insecure Default File Permissions in Local Filesystem Memory Tool

Vendor Anthropics
Product anthropic-sdk-python
Weakness CWE-276
Published March 31, 2026
Last update April 1, 2026

CVSS base score

4.8/10
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

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.

Key dates

Disclosure timeline

March 31, 2026 CVE published
April 1, 2026 Record updated