CVE-2026-34452 MEDIUM

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

Vendor Anthropics
Product anthropic-sdk-python
Weakness CWE-59
Published March 31, 2026
Last update April 3, 2026

CVSS base score

5.8/10
Attack vector Local
Attack complexity High
Privileges required Low
User interaction None
Confidentiality
Integrity

CVSS vector

CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N

What the vulnerability does

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.

Key dates

Disclosure timeline

March 31, 2026 CVE published
April 3, 2026 Record updated