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

Published Apr 29, 2026
·
Updated

Claude SDK for TypeScript provides access to the Claude API from server-side TypeScript or JavaScript applications. From version 0.79.0 to before version 0.91.1, 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. This issue has been patched in version 0.91.1.

Other sources

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.

— GitHub

Affected Software

2 affected componentsFixes available
npm/@anthropic-ai/sdk>=0.79.0<0.91.1
0.91.1
Anthropic Claude SDK for TypeScript>=0.79.0<0.91.1

Event History

Apr 29, 2026
Advisory Published
via GitHub·10:28 PM
Data Sourced
via GitHub·10:28 PM
DescriptionWeaknessAffected Software
May 4, 2026
CVE Published
via MITRE·06:41 PM
Data Sourced
via MITRE·06:41 PM
DescriptionWeakness
Data Sourced
via NVD·07:16 PM
DescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2026-41686?

CVE-2026-41686 has a high severity due to its potential to expose files and directories to unauthorized users.

2

How do I fix CVE-2026-41686?

To fix CVE-2026-41686, update the @anthropic-ai/sdk package to version 0.91.1 or later.

3

Which versions of the @anthropic-ai/sdk are affected by CVE-2026-41686?

CVE-2026-41686 affects versions of the @anthropic-ai/sdk from 0.79.0 to 0.91.0.

4

What is the risk associated with CVE-2026-41686?

The risk of CVE-2026-41686 is that sensitive data may be exposed or modified due to improper file permissions.

5

Is CVE-2026-41686 a vulnerability present in Node.js applications?

Yes, CVE-2026-41686 primarily affects Node.js applications using the Anthropic TypeScript SDK due to default permission settings.

Company

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Contact

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