CVE-2026-34450: Anthropic Claude SDK For Python Has Vulnerability

MODERATE
Advisory Identifier: GHSA-q5f5-3gjm-7mfm
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CWE-732 CWE-276
Published
Advisory Summary

CVE-2026-34450 is a MODERATE claude sdk for python has vulnerability (CWE-732: Incorrect Permission Assignment for Critical Resource) affecting Anthropic libraries in the PyPI ecosystem. The issue involves claude sdk for python has insecure default file permissions in local filesystem memory tool. Remediation is available by upgrading affected packages to version 0.87.0.

CVE-2026-34450 at a Glance

CVE Identifier CVE-2026-34450
GHSA Identifier GHSA-q5f5-3gjm-7mfm
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-732: Incorrect Permission Assignment for Critical Resource
Affected Product Anthropic
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-34450

To remediate this vulnerability, upgrade all affected Anthropic dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

anthropic fixed: 0.87.0 
pip install anthropic>=0.87.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show anthropic

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-34450, inspect your installed packages using pip:

pip show anthropic

Analyze the terminal output to locate any version of Anthropic in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.87.0), your application is affected.

Note: The pip show anthropic command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-732: Incorrect Permission Assignment for Critical Resource, where the product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors. In Anthropic, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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`](https://hackerone.com/lucasfutures) on HackerOne for the report.

CVE-2026-34450 Affected Anthropic Versions

1 component(s)
Fixed Versions:
0.87.0
Product / Package Ecosystem Affected Versions Fixed Version
anthropic
pypi/anthropic
PyPI
≥ 0.86.0
< 0.87.0
0.87.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/anthropics/anthropic-sdk-python/security/advisories/GHSA-q5f5-3gjm-7mfm
NVD — CVE-2026-34450 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-34450
Security Fix Commit FIX COMMIT
https://github.com/anthropics/anthropic-sdk-python/commit/715030ceb4d6dd8d3546e999c680e29532bf1255
Anthropic Source Repository REPOSITORY
https://github.com/anthropics/anthropic-sdk-python
Anthropic Release RELEASE
https://github.com/anthropics/anthropic-sdk-python/releases/tag/v0.87.0

Frequently Asked Questions

What is CVE-2026-34450?
CVE-2026-34450 is a security vulnerability in Anthropic involving Claude SDK for Python has Insecure Default File Permissions in Local Filesystem Memory Tool under CWE-732: Incorrect Permission Assignment for Critical Resource.
Which Anthropic versions are affected?
Affected versions include releases prior to 0.87.0 across affected packages: anthropic.
What version fixes CVE-2026-34450?
Upgrading to 0.87.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is anthropic affected?
Yes, anthropic is affected in releases prior to 0.87.0. Upgrade your dependency to 0.87.0 or later.
What CWE is associated with CVE-2026-34450?
CVE-2026-34450 is classified under CWE-732: Incorrect Permission Assignment for Critical Resource (The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.).
How can I check PyPI dependencies for CVE-2026-34450?
Run the dependency tree command: 'pip show anthropic'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q5f5-3gjm-7mfm",
  "modified" : "2026-04-01T21:15:30Z",
  "published" : "2026-04-01T21:15:30Z",
  "aliases" : [ "CVE-2026-34450" ],
  "summary" : "Claude SDK for Python has Insecure Default File Permissions in Local Filesystem Memory Tool",
  "details" : "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.\n\nUsers on the affected versions are advised to update to the latest version.\n\nClaude SDK for Python thanks [`lucasfutures`](https://hackerone.com/lucasfutures) on HackerOne for the report.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "anthropic"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0.86.0"
      }, {
        "fixed" : "0.87.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/anthropic-sdk-python/security/advisories/GHSA-q5f5-3gjm-7mfm"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34450"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/anthropic-sdk-python/commit/715030ceb4d6dd8d3546e999c680e29532bf1255"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/anthropics/anthropic-sdk-python"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/anthropics/anthropic-sdk-python/releases/tag/v0.87.0"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-276", "CWE-732" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-01T21:15:30Z",
    "nvd_published_at" : "2026-03-31T22:16:19Z"
  }
}