AI agent vulnerability · Anthropic SDKs

CVE-2026-41686: Claude SDK for TypeScript has Insecure Default File Permissions in Local Filesystem Memory Tool

mediumCVSS 4.0 4.8GHSA-p7fg-763f-g4gf

The BetaLocalFilesystemMemoryTool in the Anthropic TypeScript SDK created memory files and directories using the Node.js default modes (0o666 for files, 0o777 for directories), 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.

Published Apr 29, 2026 · Updated May 21, 2026

Affected packages

@anthropic-ai/sdk

Ecosystem: npm
Affected: >= 0.79.0, < 0.91.1
Fixed in: 0.91.1
Check: npm ls @anthropic-ai/sdk

Advisory details

From the GitHub Advisory Database (CC BY 4.0).

The BetaLocalFilesystemMemoryTool in the Anthropic TypeScript SDK created memory files and directories using the Node.js default modes (0o666 for files, 0o777 for directories), 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.

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

Claude SDK thanks lucasfutures 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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