CVE-2026-41686

Description

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.

CVSS v3.1 Score

4.4

MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

EPSS — Exploit Prediction

0.0001

Probability of exploitation

0.02%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-732 CWE-732

Affected Products

Vendor	Product	Versions
anthropic	claude_sdk_for_typescript	0.79.0 — 0.91.1

References

Advisories & Patches

https://github.com/anthropics/anthropic-sdk-typescript/security/advisories/GHSA-p7fg-763f-g4gf

Frequently Asked Questions

What is CVE-2026-41686? +

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. It has a CVSS v3.1 base score of 4.4 (MEDIUM).

How severe is CVE-2026-41686? +

CVE-2026-41686 has a CVSS v3.1 score of 4.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0001, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-41686? +

CVE-2026-41686 affects products from anthropic, specifically: claude_sdk_for_typescript. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-41686? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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