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Vulnerability · Published Mar 31, 2026 · Assigned by GitHub_M

CVE-2026-34451Claude SDK for TypeScript: Memory Tool Path Validation Allows Sandbox Escape to Sibling Directories

Medium 6.3

In plain English

A medium-severity path traversal 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 0.4% (higher than 30% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)6.3Medium
Exploit odds (30 days)0.4%top 69.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

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 0.81.0, the local filesystem memory tool in the Anthropic TypeScript SDK validated model-supplied paths using a string prefix check that did not append a trailing path separator. A model steered by prompt injection could supply a crafted path that resolved to a sibling directory sharing the memory root's name as a prefix, allowing reads and writes outside the sandboxed memory directory. This issue has been patched in version 0.81.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
npm@anthropic-ai/sdk0.81.0GHSA-5474-4w2j-mq4c

Affected products (as reported)

VendorProductVersions
anthropics anthropic-sdk-typescript >= 0.79.0, < 0.81.0

Weakness: CWE-22, CWE-41 · Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

References