{
  "schema_version": "1.6.0",
  "id": "ACVE-2026-0525",
  "aliases": [],
  "published": "2026-09-10T00:00:00Z",
  "firstReported": {
    "date": "2026-09-10",
    "url": "https://www.anthropic.com/threat-intelligence-report-september-2026",
    "publisher": "Anthropic"
  },
  "modified": "2026-09-25T00:00:00Z",
  "summary": "Breached at least four European websites, exfiltrated about 140,000 political-opinion records and targeted credentials and reader sessions: GTG-50029 hacktivists with Claude in an agent framework.",
  "details": "## What\n\nAnthropic says a French-speaking actor used Claude and sub-agents to target European political parties, media, think tanks and their service providers. The campaign compromised at least four websites, including a political campaign platform from which about 140,000 records containing political opinions were exfiltrated.\n\n## Detection\n\nAnthropic identified and disrupted the campaign. Recorded from Anthropic's September 2026 threat report. Not recreated in a lab.\n\n## Fix\n\nTreat agent frameworks and exposed API keys as privileged infrastructure, limit access to political and identity data, and monitor automated multi-site activity.",
  "affected": [
    {
      "package": {
        "ecosystem": "AgentHarness",
        "name": "claude"
      },
      "ranges": [
        {
          "type": "SEMVER",
          "events": [
            {
              "introduced": "0"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "type": "REPORT",
      "url": "https://www.anthropic.com/threat-intelligence-report-september-2026"
    },
    {
      "type": "ARTICLE",
      "url": "https://thenextweb.com/news/anthropic-claude-misuse-threat-intelligence-report"
    }
  ],
  "database_specific": {
    "severity": "HIGH",
    "acve": {
      "specVersion": 1,
      "status": "candidate",
      "kind": "behavioural",
      "vulnClasses": [
        "credential-theft",
        "data-exfiltration",
        "over-privileged-combination"
      ],
      "cwe": [
        "CWE-522",
        "CWE-359",
        "CWE-693"
      ],
      "taxonomy": {
        "atlas": [
          "AML.T0124",
          "AML.T0116",
          "AML.T0049"
        ]
      },
      "noCveReason": "No code defect: the harm arises from the attacker using an agent framework to pursue the campaign.",
      "cveBoundary": "behavioural",
      "threat": {
        "attacker": "user",
        "vector": "unsafe-default",
        "outcome": "exfiltration"
      },
      "evidence": [
        {
          "kind": "incident",
          "url": "https://www.anthropic.com/threat-intelligence-report-september-2026"
        }
      ],
      "fix": {
        "summary": "The operator was the attacker, so the control that protects victims is the model provider's: Anthropic disrupted the campaign and strengthened safeguards.",
        "actions": [
          {
            "type": "reconfigure",
            "target": "anthropic.safeguards",
            "to": "strengthened after the campaign was disrupted",
            "why": "Shipped by Anthropic: it disrupted GTG-50029 and strengthened safeguards.",
            "owner": "model-provider"
          }
        ]
      },
      "exposure": {
        "harness": {
          "value": "An agent framework using Claude and sub-agents",
          "any": false,
          "status": "confirmed",
          "source": "https://www.anthropic.com/threat-intelligence-report-september-2026"
        },
        "model": {
          "value": "Claude",
          "any": false,
          "status": "confirmed",
          "source": "https://www.anthropic.com/threat-intelligence-report-september-2026"
        },
        "goal": {
          "value": "Target European political, media and affiliated entities",
          "stated": true,
          "status": "confirmed",
          "source": "https://www.anthropic.com/threat-intelligence-report-september-2026"
        },
        "tools": {
          "value": "Agent framework with sub-agents for reconnaissance, code review and findings triage",
          "status": "confirmed",
          "source": "https://www.anthropic.com/threat-intelligence-report-september-2026"
        },
        "approval": {
          "value": "The operator delegated multi-stage campaign work to sub-agents",
          "mode": "auto-approve",
          "status": "confirmed",
          "source": "https://www.anthropic.com/threat-intelligence-report-september-2026"
        },
        "inputControl": "operator",
        "agentAction": "The agent framework conducts reconnaissance and intrusions and processes data from multiple victims.",
        "harm": "data-exfiltration",
        "divergence": "decomposed-misuse",
        "reach": {
          "value": "Victim websites, political records and user credentials",
          "kinds": [
            "private-repositories",
            "network",
            "messaging"
          ],
          "status": "confirmed",
          "source": "https://www.anthropic.com/threat-intelligence-report-september-2026"
        },
        "condition": {
          "value": "When the operator supplied stolen API access to an agent framework that managed sub-agents",
          "status": "confirmed",
          "source": "https://www.anthropic.com/threat-intelligence-report-september-2026"
        },
        "scale": {
          "statement": "About 140,000 records were exfiltrated from one political campaign platform",
          "unit": "records",
          "value": 140000,
          "source": "https://www.anthropic.com/threat-intelligence-report-september-2026"
        }
      },
      "occurrence": {
        "basis": "real-use",
        "reportedBy": "vendor",
        "responses": [
          {
            "party": "Anthropic",
            "status": "fixed",
            "statement": "Anthropic says it disrupted the activity and strengthened safeguards.",
            "source": "https://www.anthropic.com/threat-intelligence-report-september-2026"
          }
        ]
      },
      "exploitation": {
        "status": "none-known",
        "checkedAt": "2026-09-24T00:00:00Z",
        "sources": [
          {
            "url": "https://www.anthropic.com/threat-intelligence-report-september-2026",
            "type": "research",
            "note": "Anthropic reported a real hacktivist campaign."
          }
        ],
        "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"
    }
  }
}