CVE-2026-34452: Claude SDK for Python: Memory Tool Path Validation Race Condition Allows Sandbox Escape

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% 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-59

Description

The Claude SDK for Python provides access to the Claude API from Python applications. From version 0.86.0 to before version 0.87.0, the async local filesystem memory tool in the Anthropic Python SDK validated that model-supplied paths resolved inside the sandboxed memory directory, but then returned the unresolved path for subsequent file operations. A local attacker able to write to the memory directory could retarget a symlink between validation and use, causing reads or writes to escape the sandbox. The synchronous memory tool implementation was not affected. This issue has been patched in version 0.87.0.

Affected products

anthropics anthropic-sdk-python: from 0.86.0 before 0.87.0 — fixed in 0.87.0

How to fix

Upgrade to a fixed version: anthropics anthropic-sdk-python 0.87.0. Check the vendor advisory for mitigations.

References

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