Researchers Use Claude Opus 5 to Hijack OpenAI Employee Accounts for Under $3,000
FinanceYF5 · x · 2026-09-20
Three security researchers demonstrated a full attack chain against OpenAI using Claude Opus 5:
- Started from an image upload vulnerability and escalated it into OpenAI employee account takeover
- Used the compromised account's Codex to submit a PR to OpenAI's internal Monorepo
- Total token cost of the attack: under $3,000
- Notably, Opus 4.8 consistently failed at the exploit, but Opus 5 pulled it off within hours of release
The case highlights a sharp jump in frontier models' offensive capabilities, dropping the cost barrier for AI-assisted attacks to trivial levels.
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