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

> Local attackers can read or modify agent memory files due to insecure default permissions in the Claude TypeScript SDK.

- **Severity:** Medium 4.8 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 4 May 2026
- **Updated:** 5 May 2026
- **Also known as:** GHSA-p7fg-763f-g4gf, MINI-6c97-m979-9qgf

## What is CVE-2026-41686?

CVE-2026-41686 is a medium-severity vulnerability in anthropics anthropic-sdk-typescript, published on 4 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### 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.

Weakness: CWE-732 (Incorrect Permission Assignment for Critical Resource)

## Which versions are affected by CVE-2026-41686?

2 open source packages ship an affected version, including @anthropic-ai/sdk. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@anthropic-ai/sdk` | npm | From 0.79.0 | 0.91.1 |
| `@anthropic-ai/sdk` | npm | From 0.79.0 | 0.91.1 |

Products: Anthropic Claude Sdk for Typescript.

## How do I fix CVE-2026-41686?

Upgrade @anthropic-ai/sdk to 0.91.1 or later.

## Is CVE-2026-41686 being exploited?

There is no known exploitation of CVE-2026-41686 in the wild and no public exploit code.

## Other vulnerabilities in anthropics anthropic-sdk-typescript

- [CVE-2026-34451](https://insights.sbomify.com/CVE-2026-34451/): Claude SDK for TypeScript: Memory Tool Path Validation Allows Sandbox Escape to Sibling Directories (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-41686 and fix it if it is affected.

What it is: CVE-2026-41686 is a medium-severity vulnerability in anthropics anthropic-sdk-typescript, published on 4 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-41686 in the wild and no public exploit code.

Affected packages and fixed versions:
- @anthropic-ai/sdk (npm): affected from 0.79.0; fixed in 0.91.1
- @anthropic-ai/sdk (npm): affected from 0.79.0; fixed in 0.91.1

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-41686/ (Markdown: https://insights.sbomify.com/CVE-2026-41686/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-41686
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-41686
- OSV: https://osv.dev/vulnerability/CVE-2026-41686

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-41686/
Summaries are generated and may contain mistakes; the official description above is the record.