Claude SDK for Python: Memory Tool Path Validation Race Condition Allows Sandbox Escape
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!
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | anthropic | >= 0.86.0, < 0.87.0 | 0.87.0 |
References
- https://github.com/anthropics/anthropic-sdk-python/releases/tag/v0.87.0
- https://github.com/anthropics/anthropic-sdk-python/security/advisories/GHSA-w828-4qhx-vxx3
- https://github.com/anthropics/anthropic-sdk-python/commit/6599043eee6e86dce16953fcd1fd828052052be6
- https://nvd.nist.gov/vuln/detail/CVE-2026-34452
- https://github.com/anthropics/anthropic-sdk-python
- CVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N- Weakness (CWE)
CWE-367, CWE-59- Platform
- Python (PyPI)
- Package
anthropic- Disclosed
- 31.03.2026
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-2115 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-w828-4qhx-vxx3 - CC BY 4.0
Vulnerability history: anthropic
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 03.2026 03.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Medium 2
Disclosures per year
- 2026: 2
-
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