GHSA-W828-4QHX-VXX3

Vulnerability from github – Published: 2026-04-01 21:17 – Updated: 2026-04-01 21:17
VLAI?
Summary
Claude SDK for Python: Memory Tool Path Validation Race Condition Allows Sandbox Escape
Details

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!

Severity ?
5.8 (Medium)
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
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "anthropic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.86.0"
            },
            {
              "fixed": "0.87.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34452"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-367",
      "CWE-59"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-01T21:17:34Z",
    "nvd_published_at": "2026-03-31T22:16:20Z",
    "severity": "MODERATE"
  },
  "details": "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.\n\nUsers on the affected versions are advised to update to the latest version.\n\nClaude SDK for Python thanks [hackerone.com/kasthelord](https://hackerone.com/kasthelord) for reporting this issue!",
  "id": "GHSA-w828-4qhx-vxx3",
  "modified": "2026-04-01T21:17:34Z",
  "published": "2026-04-01T21:17:34Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/anthropics/anthropic-sdk-python/security/advisories/GHSA-w828-4qhx-vxx3"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34452"
    },
    {
      "type": "WEB",
      "url": "https://github.com/anthropics/anthropic-sdk-python/commit/6599043eee6e86dce16953fcd1fd828052052be6"
    },
    {
      "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"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "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",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Claude SDK for Python: Memory Tool Path Validation Race Condition Allows Sandbox Escape"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.