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VulnerabilityPublished Updated

CVE-2026-41686: @anthropic-ai/sdk · Claude SDK for TypeScript has Insecure Default File Permissions in Local Filesystem Memory Tool

Affects @anthropic-ai/sdkSource GCVE Database

0
Authoritative record:CVE-2026-41686· Medium 4.8

Not known to be exploited · CVSS 4.8 Medium : upgrade to 0.91.1 when convenient.

Data as of 27 Oct 2026, 00:07 UTC

CVSS 4.0 base score
4.8Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 0.91.1
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

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade @anthropic-ai/sdk to 0.91.1.

Affected software

ProductAffectedFixed in
npm@anthropic-ai/sdkAffected
  • >=0.79.0 <0.91.1
Fixed in
  • 0.91.1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

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. Users on the affected versions are advised to update to the latest version. Claude SDK thanks `lucasfutures` for the report.

References

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