GitStock

anthropics/anthropic-sdk-python · Security

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

GHSA ID
GHSA-w828-4qhx-vxx3
CVE ID
CVE-2026-34452
Severity
medium
Published
Updated
CVSS
5.3 · CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
CVSS v3
5.3 · CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
CVSS v4
5.8 · 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

Description

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.

Users on the affected versions are advised to update to the latest version.

Claude SDK for Python thanks hackerone.com/kasthelord for reporting this issue!

CWEs

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

References

Open GitHub