Vulnerability · Published May 4, 2026 · Assigned by GitHub_M
CVE-2026-41686Claude SDK for TypeScript has Insecure Default File Permissions in Local Filesystem Memory Tool
Medium 4.8
In plain English
A medium-severity incorrect permission assignment in anthropic-sdk-typescript from anthropics. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @anthropic-ai/sdk | 0.91.1 | GHSA-p7fg-763f-g4gf |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| anthropics | anthropic-sdk-typescript | >= 0.79.0, < 0.91.1 |
Weakness: CWE-732 · 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