GitHub Advisoryadvisory · PyPI

GHSA-w828-4qhx-vxx3 Claude SDK for Python: Memory Tool Path Validation Race Condition Allows Sandbox Escape

MEDIUM Published 2026-04-01 Modified 2026-04-24 Official page ↗
Aliases
CVE-2026-34452
Ecosystem
PyPI
Packages
anthropic
Severity
Moderate
CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
Weaknesses
CWE-367, CWE-59
Reviewed
2026-04-01

Affected packages

• PyPI anthropic: >= 0.86.0, < 0.87.0 → fixed in 0.87.0

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!

Related

Alias · CVE (1)

  • CVE-2026-34452 The Claude SDK for Python provides access to the Claude API from Python applications. vulnerability

Weakness · CWE (2)

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

References