Claude SDK for Python has Insecure Default File Permissions in Local Filesystem Memory Tool
The local filesystem memory tool in the Anthropic Python SDK created memory files with mode 0o666, leaving them world-readable on systems with a standard umask and world-writable in environments with a permissive umask such as many Docker base images. A local attacker on a shared host could read persisted agent state, and in containerized deployments could modify memory files to influence subsequent model behavior. Both the synchronous and asynchronous memory tool implementations were affected.
Users on the affected versions are advised to update to the latest version.
Claude SDK for Python thanks lucasfutures on HackerOne for the report.
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-q5f5-3gjm-7mfm
- https://github.com/anthropics/anthropic-sdk-python/commit/715030ceb4d6dd8d3546e999c680e29532bf1255
- https://nvd.nist.gov/vuln/detail/CVE-2026-34450
- https://github.com/anthropics/anthropic-sdk-python
- CVSS vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-276, CWE-732- Platform
- Python (PyPI)
- Package
anthropic- Disclosed
- 31.03.2026
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2026-2114 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-q5f5-3gjm-7mfm - 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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