CVE-2026-34452

Claude SDK for Python: Memory Tool Path Validation Race Condition Allows Sandbox Escape

State: Published
Severity: 5.8 Medium
Published: Mar 31, 2026
Updated: Apr 3, 2026
Reserved: Mar 27, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	5.8 Medium	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	GitHub_M

Weaknesses

CWE-59 Improper Link Resolution Before File Access ('Link Following')
CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition

Affected Products

Product	Versions
anthropic-sdk-pythonanthropics	>= 0.86.0, < 0.87.0Affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.