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

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-31 · updated 2026-07-24
• Weakness: CWE-22

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 products

• anthropics anthropic-sdk-typescript: from 0.79.0 before 0.81.0 — fixed in 0.81.0

How to fix

Upgrade to a fixed version: anthropics anthropic-sdk-typescript 0.81.0. Check the vendor advisory for mitigations.

References

• https://github.com/anthropics/anthropic-sdk-typescript/commit/0ac69b3438ee9c96b21a7d3c39c07b7cdb6995d9
• https://github.com/anthropics/anthropic-sdk-typescript/releases/tag/sdk-v0.81.0
• https://github.com/anthropics/anthropic-sdk-typescript/security/advisories/GHSA-5474-4w2j-mq4c

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