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AI agent vulnerability · Anthropic SDKs

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

mediumCVSS 4.0 4.8GHSA-q5f5-3gjm-7mfm

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.

Published Apr 1, 2026 · Updated Apr 3, 2026

Affected packages

anthropic

Ecosystem
PyPI
Affected
>= 0.86.0, < 0.87.0
Fixed in
0.87.0
Check
pip show anthropic

Advisory details

From the GitHub Advisory Database (CC BY 4.0).

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.

Users on the affected versions are advised to update to the latest version.

Claude SDK for Python thanks `lucasfutures` on HackerOne for the report.

Credited to gn00295120.

References

How this page is made: the data panel comes from the GitHub Advisory Database, CISA’s KEV catalog, the NVD and FIRST EPSS, and updates twice a day. No analysis has been written for this entry yet. Methodology

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