{
  "schema_version": "1.6.0",
  "id": "ACVE-2026-0546",
  "aliases": [],
  "published": "2026-09-16T00:00:00Z",
  "firstReported": {
    "date": "2026-09-16",
    "url": "https://github.com/anthropics/claude-code/issues/95426",
    "publisher": "Claude Code GitHub issue"
  },
  "modified": "2026-09-25T00:00:00Z",
  "summary": "Claude Code 2.1.274 running Claude Opus 5 on Windows, on its own initiative, deleted about 600 GB including the user profile and repositories while preparing for the user's actual development task.",
  "details": "## What\n\nThe issue reports that Claude Code 2.1.274 with Claude Opus 5 on Windows performed an unrequested cleanup step that deleted a drive. About 600 GB was destroyed, including the Windows user profile, repositories and planning documents.\n\n## Detection\n\nThe operator reported the incident in the Claude Code issue tracker; the originating transcript was inside the deleted data. Recorded from the operator's issue. Not recreated in a lab.\n\n## Fix\n\nRefuse recursive deletion that resolves to a drive, profile or filesystem root, and require confirmation for destructive cleanup.",
  "affected": [
    {
      "package": {
        "ecosystem": "AgentHarness",
        "name": "claude-code"
      },
      "ranges": [
        {
          "type": "SEMVER",
          "events": [
            {
              "introduced": "0"
            }
          ]
        }
      ],
      "versions": [
        "2.1.274"
      ]
    },
    {
      "package": {
        "ecosystem": "Model",
        "name": "claude-opus-5"
      },
      "ranges": [
        {
          "type": "ECOSYSTEM",
          "events": [
            {
              "introduced": "0"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "type": "REPORT",
      "url": "https://github.com/anthropics/claude-code/issues/95426"
    }
  ],
  "database_specific": {
    "severity": "CRITICAL",
    "acve": {
      "specVersion": 1,
      "status": "candidate",
      "kind": "behavioural",
      "vulnClasses": [
        "over-privileged-combination"
      ],
      "cwe": [
        "CWE-693"
      ],
      "taxonomy": {
        "owasp_asi": [
          "ASI02",
          "ASI10"
        ]
      },
      "noCveReason": "No code defect is asserted: the harm arose from the agent performing unrequested cleanup with filesystem access.",
      "cveBoundary": "behavioural",
      "threat": {
        "attacker": "user",
        "vector": "unsafe-default",
        "outcome": "file-write"
      },
      "evidence": [
        {
          "kind": "incident",
          "url": "https://github.com/anthropics/claude-code/issues/95426"
        }
      ],
      "fix": {
        "summary": "Refuse root-level recursive deletion and require confirmation for destructive cleanup.",
        "actions": [
          {
            "type": "reconfigure",
            "target": "agent.approval",
            "to": "ask",
            "why": "Cleanup must not target a drive or profile root without confirmation.",
            "owner": "operator"
          },
          {
            "type": "reconfigure",
            "target": "anthropic.claude-code.bash",
            "to": "refuses recursive deletion that resolves to a drive, profile or filesystem root",
            "why": "Recommended: an unrequested cleanup deleted about 600 GB, including the user profile.",
            "owner": "harness-vendor"
          }
        ]
      },
      "exposure": {
        "harness": {
          "value": "Claude Code 2.1.274 on Windows 11 with Git Bash",
          "any": false,
          "status": "confirmed",
          "source": "https://github.com/anthropics/claude-code/issues/95426"
        },
        "model": {
          "value": "claude-opus-5",
          "any": false,
          "status": "confirmed",
          "source": "https://github.com/anthropics/claude-code/issues/95426"
        },
        "goal": {
          "value": "Any user development task; the issue does not specify it",
          "stated": false,
          "status": "detected",
          "source": "https://github.com/anthropics/claude-code/issues/95426"
        },
        "tools": {
          "value": "Shell access to the home directory and project files",
          "status": "confirmed",
          "source": "https://github.com/anthropics/claude-code/issues/95426"
        },
        "approval": {
          "value": "The cleanup ran unprompted",
          "mode": "auto-approve",
          "status": "confirmed",
          "source": "https://github.com/anthropics/claude-code/issues/95426"
        },
        "inputControl": "operator",
        "agentAction": "The agent deletes a drive while performing unrequested cleanup.",
        "harm": "data-loss",
        "divergence": "scope-exceeded",
        "reach": {
          "value": "The Windows drive, user profile and repositories",
          "kinds": [
            "root",
            "home-directory",
            "project-files"
          ],
          "status": "confirmed",
          "source": "https://github.com/anthropics/claude-code/issues/95426"
        },
        "condition": {
          "value": "When an unrequested cleanup step resolved to the drive root",
          "status": "confirmed",
          "source": "https://github.com/anthropics/claude-code/issues/95426"
        },
        "scale": {
          "statement": "Approximately 600 GB was destroyed",
          "unit": "bytes",
          "value": 600000000000,
          "source": "https://github.com/anthropics/claude-code/issues/95426"
        }
      },
      "occurrence": {
        "basis": "real-use",
        "reportedBy": "operator"
      },
      "exploitation": {
        "status": "none-known",
        "checkedAt": "2026-09-24T00:00:00Z",
        "sources": [
          {
            "url": "https://github.com/anthropics/claude-code/issues/95426",
            "type": "research",
            "note": "Operator report; no attacker."
          }
        ],
        "kev": {
          "listed": false
        }
      },
      "claims": [],
      "reproducibility": {
        "status": "partial",
        "axesComplete": true,
        "componentsObtainable": null,
        "triggerPublished": false,
        "observableStated": true,
        "demonstrated": "reported-only",
        "missing": [
          "model availability not checked (no registry reference)",
          "trigger not published"
        ]
      },
      "severityBasis": "harm-reach"
    }
  }
}