Vulnerability in @anthropic-ai/sdk (CVE-2026-41686)
Summary
Vulnerability in @anthropic-ai/sdk (CVE-2026-41686). Risk of unauthorized operations or information disclosure. Exploitable via BetaLocalFilesystemMemoryTool. Mitigation: upgrade to 0.91.1 or later.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-41686 has been found in @anthropic-ai/sdk.
Attackers can target a specific entry point like BetaLocalFilesystemMemoryTool over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.4/10.
What to do: upgrade @anthropic-ai/sdk to 0.91.1 or later.
If unsure, ask your IT team or search "@anthropic-ai/sdk CVE-2026-41686" on the vendor's site.
CVE-2026-41686 (@anthropic-ai/sdk) — CWE-732 / CVSS v3 4.4
Attack vector: local / no user interaction
Attack surface: BetaLocalFilesystemMemoryTool / lucasfutures
Patched: 0.91.1 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-732) exists in @anthropic-ai/sdk. Attackers reach the vulnerable code path via BetaLocalFilesystemMemoryTool.
Check the vendor advisory for the affected versions of @anthropic-ai/sdk. Attack surface: BetaLocalFilesystemMemoryTool / lucasfutures.
Severity: Medium (CVSS 4.4/10). Risk of unauthorized operations or information disclosure.
Update to 0.91.1.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r '@anthropic-ai/sdk' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r '@anthropic-ai/sdk' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
@anthropic-ai/sdkを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade @anthropic-ai/sdk to 0.91.1ステージング環境で 0.91.1 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- advisory github.com
- web github.com