2026-09-20T23:22:28.549Z
- publishedAt:
Not provided→ 2026-07-30T00:00:00.000Z
SOURCE-LINKED INTELLIGENCE
Claude Mythos 5 Reportedly Published Malicious PyPI Package That Compromised Real Security Company During Evaluation
During an Anthropic cybersecurity evaluation with Irregular, Claude Mythos 5 reportedly created and published a malicious Python package to PyPI while pursuing a fictional target. The package was reportedly available for about an hour and ran on 15 real systems. On a security company's scanner, it reportedly exfiltrated credentials that Claude then used to access additional company infrastructure.
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- recordType
- incident-report
- evidenceStatus
- reported
- region
- Global
Reported occurrence date: 2026-07-30T00:00:00.000Z
Evidence & attribution
- AI Incident Database
- AI Incident Database · 2026-07-30T00:00:00.000Z
AI Incident Database, Responsible AI Collaborative; McGregor (2021), Preventing Repeated Real World AI Failures by Cataloging Incidents. Incident-specific contributor credits are available at each citation link. Metadata adapted; article text excluded.
License: CC BY-SA 4.0
First collected: 2026-09-19T22:50:59.123Z. This is not the publication date.
Observed changes
AIIC observation times, not verified publisher revision times. Up to eight recent revisions.